Which Dart SHP 4.0" or 4.125"


Staff member
Both blocks are the very same casting, therefore the 4.0" bore has another 1/16" cylinder wall thickness. I would love to be able to say I have 400 cu in sbc, but for just 23 less cubic inches (377) I would gain the extra wall thickness. This would provide more wall thickness for boring when something breaks.

On the other hand with a forged Scat crankshaft (4-350-3750-6000) and their premium pro comp rods (2-ICR6000-7/16) with 7/16" ARP rod bolts, I shouldn't have anything to worry about if max RPM is 6400 and mean piston speed is 4000 fpm.

Again this is going in a T-Bucket and only weighing 1800 lbs, I should have enough power either way I go.

Any thoughts about which block???

Rick Miller


Staff member
http://www.summitracing.com/parts/DRT-3 ... toview=sku

http://www.carcraft.com/techarticles/cc ... ewall.html

read thru this thread and its sub-links


http://www.hotrod.com/techarticles/engi ... omparison/

http://www.carcraft.com/techarticles/cc ... index.html


http://www.dartheads.com/products/aitdo ... ile_id/52/

http://www.dartheads.com/wp-content/upl ... -Block.pdf




unless your going with a turbo and a great deal of boost, or a hell of a load of nitrous, ID sure go with a 4.125" bore block as theres no reason to go with the smaller bore , there casting the blocks so the minimum wall Cylinder Wall Thickness, min. ................................…… .230" @ 4.165" bore

DART Iron Small Block - Technical Notes
Deck Height ..................................................... 9.025"
Bore ..................................................... 4.00" or 4.125" unfinished
Main Bearing Size ..................................................... 350 (2.45")
Weight ..................................................... 175 lbs
Largest Recommended Bore ................................…… 4.165"
Camshaft Bearing Diameter ................................…… SBC - 2.00"
Camshaft Position ..........................................……… Standard SBC
Cylinder Wall Thickness, min. ................................…… .230" @ 4.165" bore
Deck Thickness, min ..........................................……… .675"
Torque Specs - Main Caps 1 - 5 7/16" bolts 65 ft lbs
2,3,4 outers 3/8" bolts 35 ft lbs

Dart SBC Iron Block
Part# 31161111 31161211
Material: Superior iron alloy
Bore: 4.00” or 4.125” unfinished
Bore & stroke: 4.165” x 3.750” max recommended
Cam bearing bore ID: SBC - 2.00”
Cam bearings: Special coated, grooved, w/3 oil holes
Cam Bearing O.S. + .010”, +.020”, +.030”
Cam bearing press: .002”
Cam journal OD: Standard SBC - 1.869”
Cam Plug: 2.106” dia. cup plug
Cylinder Wall Thickness: .230” min @ 4.165” bore
Deck Height: 9.025”
Deck Thickness: .675” min.
Fuel Pump: Mechanical pump provision
Fuel Pump Pushrod: Standard Length
Freeze Plugs: Press in cup plugs
Lifter Bores: SBC .8427” - .8437”
Lifters: Designed for factory 87-95 Hyd rollers, must use +.300 tall lifters if using
link bar lifters
Main bearing size: 2.450”
Main bearing bore: 2.6405”-2.6415”
Main Cap Bolts: #1-#5 7/16
#2, #3, #4 3/8” splayed
Main cap press: .005”
Main caps: Ductile Iron -
Main cap register: Deep stepped register on each side (no need for dowels)
Oil system: Wet Sump - Main Priority Oiling
Oil Pump shaft: 350 main = Stock shaft (.481” OD)
Oil Filter: Standard SBC filter, uses 2 bolt filter adapter
Oil Pan: Standard 1980-1985 SBC oil pan
Rear Main Seal 350 main - std seal
Serial No. Left front & main caps
Starter: Standard SBC
Stud holes, Head: Blind holes
Timing chain/gears Standard SBC components, will also accommodate 87-95 thrust plate
Timing Cover: Can use stock cover
Torque Specs: #1-#5 7/16” bolts - 65 ft lbs
#2,#3,#4 3/8” bolts - 35 ft lbs
Weight: 175 lbs @ 4.00” bore

http://www.carcraft.com/techarticles/cc ... index.html

Dart Machinery's Little M Sportsman Chevy Small-Block - Quick Tech
From the October, 2010 issue of Car Craft
By John McGann
Photography by John McGann

Ccrp 1010 Dart Machinerys Little M Sportman Chevy Small Block Engine
Dart's Little M Sportsman
Dart Machinery was founded in a backyard garage nearly 30 years ago by Richard Maskin. The company makes aftermarket engine blocks at a variety of price points for small and big Chevrolets and Fords. We have access to one of its Little M Sportsman Chevy small-blocks and thought we'd take the opportunity to compare it side-by-side with a production Chevy small-block at JMS Racing Engines in El Monte, California.

A. Siamesed Bores
That's JMS' block machinist Sal Alcaraz shining his flashlight down the water jacket of the production Chevy block. Look into the core plug opening-see the sliver of light between the cylinders? This block is non-Siamese: The barrels of the cylinders do not touch. All production small-blocks except for the relatively rare 400s are cast this way. The Dart block has Siamese cylinders-they touch each other in a row at the 3 o'clock and 9 o'clock positions. This makes the cylinders very rigid, which results in a better ring seal.

B. Deck Thickness
The Dart block has a deck thickness of 0.675 inch. With a production block, you'd be lucky to find one with a 0.400-inch-thick deck. You get a better head gasket seal, perfect for high-compression or power-adder applications. All the cylinder head bolts in the Dart block are blind-they don't open into the water jackets like a production block. This prevents any chance of coolant from seeping up the head bolts and eventually creeping into the cylinders.

C. Cylinders
You can get a Dart Little M Sportsman block in either 4.00- (350) or 4.125-inch (400) bore sizes. However, you can bore the Dart blocks out to a maximum 4.185 inches. That's bigger than you could ever dare go with a production block. The deck height is 9.025 inches-the same as a production, as are nearly all the other dimensions of this Little M. You have a choice of either standard 350 main bearing journal sizes, which are 2.450 inches, or the slightly bigger journals of a 400 at 2.650 inches. The rear main seal for all Little M Sportsman blocks is the early two-piece design.

D. Crankcase Clearance
A production 400 engine came with a 3.75-inch stroke, and that crankshaft is what guys use to build 383s out of a 350 block. The maximum stroke Dart recommends is 3.875 inches. Combine that with a maximum 4.185-inch bore, and you will have a 426.4ci engine. Better call it a 427, though.

E. Main Caps
Most small-blocks came with two-bolt main caps from the factory. You don't need a lot of clamping force in a 175hp Malibu engine. The Little M also has four-bolt main caps, but notice that the outer bolts are situated at an angle rather than straight like the production caps. This splayed bolt design is superior because it spreads the clamp load over a much wider surface than the straight cap design. The caps themselves are made with ductile iron rather than the cast-iron alloy used at the factory. It is stronger and less resistant to fatigue and cracking than the factory material.

One of the biggest improvements over a stock block is Dart's oiling system. Dart's block deviates from the production block by sending filtered oil from the pump to the main bearings first. After building pressure at the mains, oil goes to the cam bearings and lifters, then on to the cylinder heads through the push-rods. This priority main oiling system differs from a production block that sends oil to the cam bearings first before the main bearings. Priority main oiling is better because the crankshaft is subjected to much greater forces than a camshaft. There are additional bosses cast into the lifter valley that can be drilled for a dry-sump scavenging.

Which One to Buy?
Dart's tech guys told us sales are split right down the middle for 4.00- or 4.185-inch blocks. Since the price for either bore size is the same, we wondered why anyone would buy a 4.00-inch-bore block when the 4.125-inch block costs the same. Some racing classes limit bore size to 4.00 inches, some guys have a bad block but good 4-inch internals, and some guys just want a 4.00-inch-bore block to build a 327 or 350 to match the badges on their fenders. Otherwise, buy the 4.125-inch Little M Sportsman and build yourself a big small-block.
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Staff member
unless your going with a turbo and a great deal of boost, or a hell of a load of nitrous, ID sure go with a 4.125" bore block as theres no reason to go with the smaller bore , there casting the blocks so the minimum wall Cylinder Wall Thickness, min. ................................…… .230" @ 4.165" bore

Can you elaborate a little more on this. It seems to me that if something breaks and goes thru the cylinder, then it could easily put a very deep gouge in the wall. It seems that you think that any cylinder wall gouge could be easily removed without boring too far. I know anything is possible and you cannot guarantee that nothing bad will happen, I'm just wanting more discussion about why you don't seemed to be concerned.


Rick Miller


Staff member
a block with a larger bore diam. generally un-shrouds valves and allows the ports to flow slightly better.

every inch of displacement your engine gains tend to potentially add at least 1-1.5 horsepower and 1-1.5 more foot pound of torque to your engines power curve

With a bore size a shade under 4 inches, this Dart block has over 400-thousandths wall thickness on the minor thrust side (arrow) of the bore, and nearly 500-thousandths on the major thrust side.


http://www.popularhotrodding.com/tech/0 ... index.html




cylinder damage normally falls in three basic category,s

expected bore wear,
which varies with the engines age,and mileage and stress levels,intended use, and the quality of lubrication, a simple minor hone and re ring job and installing the original pistons can usually suffice.bore wear is cosmetic or very minor

here a thick cylinder wall adds rigidity and it helps a good deal and the after market blocks are made from better quality casting metal and thicker so they tend to flex less

minor damage , or distortion under load
which varies with the engines components used,and mileage and stress levels, heat and the quality of lubrication, and frequently can be corrected with a minor bore increase or re-bore, because the bore wear or damage exceeds a .001 depth,bore damage from a busted ring, detonation, or other causes frequently falls in this realm
here a thick cylinder wall adds rigidity and it helps a good deal,your aftermarket blocks thicker walls tend to distort measurably less under bolt clamp loads and the bores tend to stay closer to 100% round and the after market blocks are made from better better quality casting metal and thicker so they tend to flex less
a DART block with a 4.165 bore will be thicker and much more rigid than most stock OEM 400 blocks were in the original bore size

major damage
cracked bores, busted cylinder walls etc. usually the block requires re-sleeve work, or its beyond repair, and that is usually the result of a busted valve, piston or rod and it won,t matter a great deal about your original wall thickness, if a rod comes loose at 6000rpm



sleeving the bore,some times its the only way to save a block, but your very unlikely to need this type of work on a well assembled DART or AFTERMARKET BLOCK, all these examples were bored to under .100 thick
short answer is that unless your dealing with a major component failure the thicker aftermarket blocks and better metal tend to flex less and distort less, but if a crank snaps or a rod comes off a crank or a pistons destroyed by hitting a valve or detonation, its not going to matter much in the final resulting damage,(although in some cases, the thicker aftermarket casting will be easier to re-sleeve)

if you check you'll find that stud girdle use does little or nothing for the individual main cap strength but it does marginally increase main cap stability and block flex.
now the potential difference is probably not worth the expense, in that your generally spending cash that would be better used in the purchase of the stronger aftermarket block casting from a known source like DART.
look through the links and read the sub links
the billet splayed main caps on the aftermarket block is the stronger route, but Id bet 90% of the guys building their first engine think they will save money using the O.E.M. block they already own.....well, until... they add up all the machine work costs and price of parts like aftermarket splayed caps, ARP main studs ,the labor costs from the machine shop, etc. but by that time the machine shop owner is smiling all the way to the bank, and youve just figured out the true cost of that cheaper O.E.M BLOCK


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Staff member
That's exactly what I was looking for, just your thought process for going with the larger bore SHP block. Now I understand the WHY in your suggestion to go with the 4.125" bore.

I guess what Clint Eastwood said, kinda applies here....."How lucky do you feel?" ;)

Thanks again!!!

Rick Miller


Staff member
now I have little doubt this comparison posted below is mostly based on selling the concept of the economic values of darts SHP blocks but read it any way!
keep in mind most machine shops I have dealt with will try to get you to put as much time and machine work into a used block as they can reasonably get you and your wallet to part with.
you might not need everything listed done to a used block, but remember the DART blocks got a good deal more cylinder wall and web strength/thickness
http://www.dartheads.com/dart-news/deba ... ock-block/


Staff member
I found this posted I thought it was very interesting

"Dart VS. Chinablock Metallurgy and Brinell Numbers...FACTS inside
So you may have noticed a certain Chinablock fanboy spouting off lately, bumping YEARS old threads and such pimping the Chinese blocks and talking massive amounts of shit regarding the Dart blocks. I did a little investigating, being a Machinist I have been curious about composition and Brinell numbers surrounding the Dart SHP and the Chinese blocks, as said fanboy claims, and I quote, "cast with the same OE type gray iron" and "thicker and heavier casting than the Dart SHP", I found some real world numbers regarding composition and Brinell hardness as tested.

As you know, some of the key ingredients in cast iron which give strength are Nickel, Molybdenum and Copper. The numbers are as follow:

The Little-M nickel content is 0.149, Molybdenum 0.211, Copper 0.404

Dart SHP Nickel content is 0.071, Molybdenum .016, Copper 0.283

Chinablock Nickel content is 0.005, Molybdenum 0.005, Copper 0.020

Regarding the Brinell hardness, the testing was done using the Rockwell B scale and then converted to Brinell numbers.

Dart SHP tested at 190HB and the Chinablock came in at 107HB.

All testing was performed by Leo at R&L Engines in Dover, New Hamphire. "


Staff member
James Lawrence said:
We did an article on the Dart SHP block, thought you guys might want to check it out - the entire article is below.

TO WATCH THE VIDEO, click here --> http://www.streetlegaltv.com/forum/dart ... -1853.html

Good-condition 350 cube Chevy 4-bolt small-blocks are becoming increasingly hard to find. If by some slim chance that junk ’71 Nova at the local boneyard still has a good 4-bolt block, it won't be cheap. Between buying the donor block and machine work, you'll be into it for at least $800. And, at the end of the day, you have a stock block. Of course, you can pick up a brand-new race block, but you'll spend the better part of $2,000 or more.

Until now, there have been few options in the middle. Dart realizes this problem. Their answer: The new SHP block. SHP stands for “Special High Performance." SHP is a division of Dart that was created specifically the production of this block, which incorporates a lot of the features you’ll find in their high-end blocks, but with a MSRP barely over $1,500.

The History Behind Dart’s Heads and Blocks

In the mid ’70’s, Dart's founder Richard Maskin came up with many of the innovations racers take for granted today. Raised intake runners, offset pushrods, and sheet metal intakes set the Pro Stock world on fire. Maskin started making cylinder heads out of his two-car garage in 1981. Right off the bat, he jumped into Top Fuel Hemi heads that crushed the 300-mile-per-hour and 4 second ET barriers. By 1988 Dart had made their first block, The Rocket, that came with splayed caps, wide pan rails (effectively widening the stock crankcase), a raised cam location for extra crankshaft clearance, a 4.120 bore, and a 9.3-inch deck. The additional deck height compared to GM 350 block of that era required a significant amount of fabricated parts that are commonplace today. The current versions of Dart’s iron Chevy blocks came in 1998 with the Big M and 2000 with the Little M. Lightweight alloy blocks were introduced in 1997 with the aluminum version of the Rocket block. To cover the Blue Oval end of the spectrum, Ford blocks were added to the Dart lineup in 2004.


Benefits of the SHP Block

With a long history of race block design and production, Dart had to decide which features from their high end blocks would apply to the SHP block so that it would outshine stock pieces in every important area, without sacrificing economy. Fortunately, Dart’s experience made it possible to combine affordability and durability with very few compromises.

To do this on a budget, Dart completely redesigned their tooling so the foundry creates a block that requires less machine work, allowing them to cut their block qualification time in half. Even after the SHP block has been shipped to the technology center for inspection, it does not require all the fit and finish other blocks do. Processing work such as finishing the mains, cam tunnel, and lifter bores are all now done at the machining center. Less machine time equates to less processing expense per block, without sacrificing important advantages over stock-based blocks. Let’s look at the top five key features that cross over to the SHP block from Dart’s high-end blocks:



In the eyes of many racers and professional engine builders, this is the most crucial feature. A stock 350 block sends oil to the cam before making its way to the main bearings. As a result, there is a pressure loss due to the complex route the oil has to take before it gets to the mains, and a broken cam or other oiling problem inevitably leads to crankshaft damage. Dart reconfigured the oil passages so the mains are fed with the higher-pressure oil and secondary passages are created for the cam. The added lubrication to the mains will help against spinning or scoring a bearing. I karate chopped the block in half so you can see what it looks like.



Instead of cylinders being separated by water jackets, the cylinders tie together (think of two 8’s on their side) and this in turn ties the whole block together. The extra support keeps the cylinder bores round and less likely to go oval under extreme temperature and pressure conditions. The SHP block is offered in a 4” and 4.125” bore diameter.



As we mentioned above, the cylinders are tied together from side to side, which adds stability to the bores. Up top, a thick deck ties the block together as well. The SHP .625” minimum deck thickness also plays a huge role in keeping the cylinders round. Having a thicker deck also means it’s more likely to stay flat, which will keep the head gasket happier (and in place). Right below the head bolt holes in the block are the water jackets. Typical stock block design leaves the bottom of these holes open to the water jacket, but the SHP’s blind bolt holes keep the studs out of the water jacket. This also keeps out the need for sealant. One important item to remember when it comes to dealing with blind bolt holes is properly installing the head studs, as they can bottom out – the studs only need to be finger-tight in the block, with the nuts taking the final torque load.



With the top end properly tied together, Dart turned their attention to keeping the crank in place. The ductile iron main caps are made from the same grade iron found on race blocks. Before you even get the caps on, the block has deep steps to accurately register the dowel pins on the caps, and take side loads off the main bolts. To help tie those caps down are thick 7/16” center bolts. The middle three caps add two additional splayed outer bolts. The outer bolt holes angle towards the meaty center of the block to firmly hold the crank in place. The outer bolts are 3/8” diameter and clear stock-style pans. Those that own a 400 cubic inch small block Chevy know that crank choices are fewer (and often more expensive) than the 350 cubic inch motors. The fact that the SHP block has the same main bearing bore as a 350 opens up a wider variety of off-the-shelf crank choices.



Our final top five feature is additional stroker crank clearance. Since it costs as much to build a stock-displacement engine as it does to pick up a few more cubes with a long-throw crank, most customers will go for the gusto and build something big. With a stock block, clearance for the big end of the rods has to be gained with a die grinder, but Dart notches the cylinder barrels at the bottom of the SHP block to clear up to a 3.75” stroke. Main bearing bulkheads are also machined for counterweight clearance.

Q&A with Jack McInnis of Dart

What does “Special High Performance” mean?
We decided on the "Special High Performance" name because we felt it was representative of the intent. The new block, [assembled] short blocks, and other products that will be marketed under the SHP name are designed as high performance components, whereas traditionally most of Dart's products have been associated with maximum-effort racing. The SHP block is priced hundreds of dollars lower than a race block, and brings a lot of value to hot rodders, bracket racers, restricted circle track classes, and others.

Look closely and you won’t find a Dart stamp on the block; is SHP its own division?
SHP is a component of Dart intended to serve a specific market segment. It is not a separate company or location.
The reason there is not a Dart logo on the block is because we wanted to allow engine builders to be able to market their own “branded” engines based on this block. Dart has always supported the local engine builders and speed shops; the SHP program is an important part of that support.

How did the whole SHP program come about?
Richard Maskin came up with the idea for the SHP block as a way to support the aftermarket manufacturers, and give local engine builders a way to be competitive with factory crate motors. The local engine builders and mom & pop speed shops built the performance aftermarket through hard work and innovation. Without them you would have no other choices than a factory crate motor, and that would not be a good thing for performance enthusiasts.

How long as this block been in R&D?
About a year and a half. After seeing the increasing presence of factory crate motors at the PRI show in 2006, Richard Maskin realized there was a need to enable the independent engine builders to compete, and a viable block would be essential to do this.

What problems did you face when designing and producing the SHP block?
One of the biggest challenges was that we were determined that the SHP block would be an American-made product. That meant we had to really put some ingenuity into the design of the foundry tooling and the machining process in order to produce a block which lives up to Dart’s standards, and make it at an affordable price.

How did Dart figure out what features to cross over from the higher-end blocks?
That was really the easy part. The priority main oiling system, siamesed cylinder bores, and 4-bolt mains were essential to making a true high-performance block. Things like provisions for dry-sump oiling and billet steel caps are not needed in the applications the SHP block was designed for.


How did Dart find a way to make the SHP block affordable without compromising the features and durability you needed?
This was a challenge, to be able to produce a very high-quality block at the price we were targeting. When we designed the foundry tooling to make the castings, a lot of thought went into simplifying the entire process. The castings incorporate many features which are machined in our race blocks. The way the blocks are machined was completely re-thought as well. We made new fixtures, which allowed us to reduce the total machining time without sacrificing the quality of the finished product. The entire manufacturing process was thoroughly re-examined.

The block looks like a different color compared to your normal iron blocks. Is the metallurgy different, or is it just a cosmetic difference?
The iron alloy differs somewhat from our race blocks. We evaluated the requirements of the SHP design and looked at all the factors which could help reduce the cost without compromising the quality. The alloy used was one of the changes which allow us to bring this block to the market at an affordable price.

Is there a new Ford SHP block on the horizon?
We are looking at the Ford blocks, but due to the fact that there are several versions it is more of a challenge than with the Chevys. We may go down that road in the future; in the mean time we will offer SHP short blocks for Fords based on our Sportsman blocks.

What are the differences in maximum horsepower between the SHP block and your race pieces, and do the SHP blocks require any different treatment by the engine builder?
The SHP block is not intended to accommodate the kind of horsepower levels which are possible with our race blocks. 600 horsepower is the recommended maximum. The SHP block is finish-machined and only requires the engine builder to final-hone the cylinders to suit the pistons before assembly, while race blocks are frequently subject to a variety of customized machining options.

Dart's Short Block Program

Another new venture for Dart is their short-block assembly area. The SHP block has sparked enough interest to have full-time engine builders assembling two variants of the SHP block, a 372 and 400 cubic inch short block. Dart is not trying to compete with their engine builders on these short blocks which is why they are offering them only in limited configurations.


Both engine configurations feature:
• Internal Balance
• Plate Honed
• Hypereutectic Flat Top Pistons with Floating Pin
• Forged 4340 I Beam Rods with 3/8" Cap Screws
• Hastings Moly Rings
• Clevite Bearings
• Coated Cam Bearings

372 will feature
• 4.125" Bore x 3.480" Stroke
• Cast Steel Crank

400 will feature:
• 4.125" Bore x 3.750" Stroke
• Forged 4340 Steel Crank

It’s clear from the parts used that Dart is building these short-blocks with one mission in mind – creating budget engines that make great power, in a professionally-built and thoroughly-tested package.

On a 372 with 180cc Dart heads, the power levels came out to 470 HP at 5600 RPM and 470 foot-pounds at 4000 RPM. On the 400 inch short block, equipped with Dart 200cc heads, power jumped to 525 HP at 6000 RPM and 525 foot pounds at 4000 RPM. Both motors were dynoed with mild hydraulic roller cams. Dart recommends keeping the horsepower to around 600 at the flywheel for any SHP-based build. But here at powerTV we like to push the limits, so we will be doing engine dyno testing that will push the SHP short-block into the low 700 horsepower range with some nitrous. Our short-block is an upgraded package that Dart offers, given our desired power numbers. The difference includes forged pistons and forged H-beam rods. Make sure you check back for updates to see the maximum horsepower per dollar we can get out of this new SHP block.


Part# 31161111 (4.000” Bore) / 31161211 (4.125” Bore)
Material: Superior iron alloy
Bore: 4.00” or 4.125” unfinished
Bore & stroke: 4.165” x 3.750” max recommended
Cam bearing bore ID: SBC - 2.00”
Cam bearings: Special coated, grooved, w/3 oil holes (not included)
Cam Bearing O.S. + .010”, +.020”, +.030”
Cam bearing press: .002”
Cam journal OD: Standard SBC - 1.869”
Cam Plug: 2-7/64” Shallow Cup
Cylinder Wall Thickness: .230” min @ 4.165” bore
Deck Height: 9.025”
Deck Thickness: .625” min.
Fuel Pump: Mechanical pump provision
Fuel Pump Pushrod: Standard Length
Freeze Plugs: Press in cup plugs – 1-5/8”
Lifter Bores: SBC .8430” - .8440”
Main bearing size: 2.450” (350)
Main bearing bore: (350) 2.6405 – 2.6415
Main Cap Bolts: #1 7/16” (2)
#2, #3, #4 7/16” (2) 3/8” splayed (2)
#5 7/16” (2)
Main caps: Class 35 Iron - 4 bolt, center 3
Main cap register: Deep stepped register on each side (no need for dowels)
Oil system: Wet Sump - Main Priority Oiling
Oil Pump shaft: 350 main = Stock shaft (.481” OD)
Oil Filter: Standard SBC filter, uses 2 bolt filter adapter
Oil Pan: Standard SBC oil pan
Rear Main Seal 350 main - std seal 2-piece
Serial No. Left front & main caps
Starter: Standard SBC
Stud Holes, Head: Blind holes
Timing chain/gears Standard SBC components
Timing Cover: Can use stock cover / Stamped Steel or Plastic
Torque Specs: 7/16” bolts - 65 ft lbs
3/8” bolts - 35 ft lbs
Weight: 175 lbs @ 4.00” bore

Dart Machinery
Web: http://www.dartheads.com, http://www.dartSHP.com
Phone: 248-362-1188


The Grumpy Grease Monkey mechanical engineer.
Staff member


keep in mind dart sells a REALLY GOOD BIG BLOCK CHEVY BLOCK
Dart Big Block Chevy Big M Engine Block

  • Siamesed Extra-Thick Cylinder Walls: Resists cracking and improves ring seal (minimum .300'' thick with 4.625'' bore).
  • Scalloped Outer Water Jacket Walls: Improves coolant flow around the cylinder barrels to equalize temperatures.
  • Four-Bolt Main Bearing Caps: In steel or ductile iron have splayed outer bolts for extra strength.
  • Crankshaft Tunnel: Has clearance for a 4.500'' stroke crank with steel rods without grinding.
  • True ''Priority Main'' Oil System: Lubricates the main bearings before the lifters.
  • Oil Filter Pad: Drilled and tapped for an external oil pump.
  • Rear Four-Bolt Cap: Uses standard oil pump and two-piece seal - no adapter required!
  • Lifter Valley Head Stud Bosses: Prevent blown head gaskets between head bolts.
  • External Block Machining: Reduces weight without sacrificing strength.
  • Simplified Install : Fuel pump boss, clutch linkage mounts and side & front motor mounts simplfy installation on any chassis.
  • Dual Oil Pan Bolt Patterns: Fits standard and notched oil pans.
  • Bellhousing Flange and Rear Main Bearing: Reinforced with ribs to resist cracks.
  • Note: Does not include cam bearings, freeze plugs, or dowels
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The Grumpy Grease Monkey mechanical engineer.
Staff member
I was recently asked about having splayed main caps installed on a O.E.M. chevy small block, (yes when I was younger I've had it done..
we all learn from making mistakes)

while theres zero doubt the addition of properly installed splayed main caps helps crank retention and helps bearing life, most machine shops charge $500-$800 to add the splayed main caps and line hone the block and deck honing the bores and other almost mandatory machine work is always going to add several hundred to almost an additional $700-$1200,
and your still working with a block that will rarely accept a .060 over bore and still have reasonably thick bore walls and structural rigidity....
yes it works, splayed cams are an option...
its also in the long term pissing money down a rat hole!
especially when you compare the total cash outlay,
of purchasing a stronger and thicker higher strength block up front,
compared to the cost of modifying the O.E.M. block,
and what you eventually have too work with at the end of either choice you've made.

UN-machined SBC blocks have a nominal 9.0" deck height,
its very common to have the deck on a previously undecked block actually measure 9.022"-9.025"


UN-machined BBC blocks have a nominal 9.8" deck height,
its very common to have the deck on a previously undecked block actually measure 9.822-9.825


heres a few related threads you really should dead through












CNC blocks said:
On the SHP blocks
Since the Dart SHP and SHP Pro blocks have come out it not really worth dealing with an OEM block that can only be bored maybe .060 over.
once we get the block from DART,
I chamfer around the main housing bores

Chamfer the freeze plug and rear cam plug hole

Tap oil galley holes deeper

I line hone the to at least the middle spec or some shops/engine builder have me line hone to the high limit, When adding studs I do see the housing bores tighten up.

Blocks are deck to the customers desired dimension

Bored if needed

Plate honed using the same hardware and gaskets to be used in the end build.

Lifter bores are checked for size and honed as needed, Most customers do a lifter bore up grade to .904 lifter and I must have the lifters for fit to the bores.

On 3.875 stroke crank I do have to add a little more clearance to the pan rails.

So far out of a couple hundred SHP block no known failures.

Like with any new block all blocks have to be check for size.
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solid fixture here in the forum
With Power Adders needed for SBC To compete No Prep Racing or a Supercharged Hero Mud truck you have to go for the Best.

SHP ok for low po street guys.