427 truck tall deck engine mods

obviously you don,t need to build a max performance engine with the most expensive parts to boost the current performance level.
what you might want to do is as previously requested start with the basics so we are sure what were working with,

let us know the heads, intake and block casting numbers,
and the result of a compression test
, it would also help to know the truck weight,
the rear gear ratio, tire height and transmission your using.

yeah most of us would love to be easily able to throw $10K-$20K, even $35K, at the problem, and order a replacement engine,a new pro built transmission and posi dana 60 differential,
rather than thinking through the options, we can afford, and dealing with our often pathetic budgets, and the knowledge that we will need to do most of the labor our self's,
but thats not realistic for most of us.
Im all too well aware of reality, Ive been supporting both my family and my son and his family since he got sick, and can,t work, on a very limited budget for the last 6-7 years.
 
Last edited:
but everywhere I go people want to look and talk. Everyone had or knew someone who had one of these trucks.
I can see why, it looks very nice indeed !!!

Where do you think your budget falls for rebuilding the engine?

This would help with tracking your machine shop costs, you would need to update the prices charged
for the different operations.
http://garage.grumpysperformance.co...et-for-tracking-your-machine-shop-costs.3423/

Figuring out your SCR and DCR is important and is intertwined with your selection of rods, pistons,
heads and camshaft. This Excel spreadsheet will help with that.
http://garage.grumpysperformance.co...comp-ratio-cranking-pressure-calculator.4458/
 
Without Stroking its not cost worthy.
496 BBC Grumpy Way.

Competiting against what LS guys do with a 5.3 L V8 & China Turbo.
All Junkyard dropped in.

No bragging rights to get your moneys worth.

Or all bragging rights and Race Go Fast.
 
To build and use a Grumpy 496 BIG BLOCK CHEVY you need a Bullet Proof Transmission and 12-bolt Differential.
Because 650-700 Ft/lbs of torque will be on Tap.
The 700R4 CAN NOT BE BUILT STRONG ENOUGH TO TAKE IT.
THE 12-BOLT DIFFERENTIAL CAN NOT BE BUILT STRONG ENOUGH TO TAKE IT.

YOU NEED A 4L80 TRANSMISSION. IT WILL COST AT LEAST $3,000 WITH A GOOD TORQUE CONVERTER & TO MAKE IT AUTO SHIFT YOU NEED A STAND ALONE COMPUTER ANOTHER $600-$1,000.
TURBO 400 WILL COST MUCH LESS. $1500 BUILT YOURSELF.

YOU NEED A DANA 60 REAR DIFFERENTIAL.
OR A 1957-64 PONTIAC 9.3 DIFF.
$2,000-$5,000 DEPENDING UPON HOW YOU BUILD IT.

It will end up costing $20,000 all together.
Just no way around.

I was planning to build and install a Grumpy 496 BBC into my 1987 Corvette Convertible.
Priced it all out on paper.....
Just not Feasable for me.

Pontiac V8 Power is.
I have Pontiac Muscle cars too.
1970 & 1963.
Oh Lord. I better get back to work and stay late. I am going to need some overtime (maybe 80 hrs. a week) for a couple of months...
 
yeah I felt the same way... decent,quality and carefully matched, component's and performance parts,
used to properly build any engine and the machine shop bills,
cost us a lot more that most of us can easily afford.
thus we have to carefully select the better values in cost vs potential performance.
and no! that does NOT always mean you need to sink a ton of cash into a project,
but its never going to be dirt cheap to build a kick butt, combo either.
theres are bargains too be had occasionally and of course a good understanding of what your trying too accomplish helps a great deal.
 
Block # 473478
Heads # 343772
Its a Tall Deck 427.

Mine the Block has no exact year casting date.
Uses the Roman Numeral Calander for day it was made.
Oldsmobile did the same and Cadillac too.
From what I read they were made in St. Catherns Niagra Falls Plant.

The Tall Deck heads will have a casting date.
Under the valvecovers.
Mine are 1984.
So I assume the block is 1984 also.
 
A 454 Chevy is an Awesome engine.
Still plenty out there.
When you build a Long Rod 454 Its an entire New Beast.
I have seen it.
Past Worlds Fastest Street Car Shoot out local in my area.
1969 Camaro.
I went to Highschool with Frank.
 
So after reading the "large" amount of info on these tall beasts, I am thinking longer rods, lighter pistons, cam, intake, carb. Doing it the budget way, I wont have to pawn my first born or my left leg. I only drive it around my neighborhood and town, up to a few local car shows. The only reason I want to do any of this is for my own enjoyment. I most likely will not take it to the track or do any racing. Just use it for personal satisfaction of hearing the exhaust and tires burning, the issue I have now is worrying that I will rev the motor to high and break something.
 
So after reading the "large" amount of info on these tall beasts, I am thinking longer rods, lighter pistons, cam, intake, carb. Doing it the budget way, I wont have to pawn my first born or my left leg. I only drive it around my neighborhood and town, up to a few local car shows. The only reason I want to do any of this is for my own enjoyment. I most likely will not take it to the track or do any racing. Just use it for personal satisfaction of hearing the exhaust and tires burning, the issue I have now is worrying that I will rev the motor to high and break something.
I thought the same thing for a while.
Talking to other Chevy Guys off this forum with lots of Street Drag race experience its not worth it.
Better off finding a 427 standard deck or 454 standard deck engine.
Low cost and no special order 1 off pistons made required.
The Tall deck 427 no one offers off the shelf pistons unless you build a 496 V8.
Buy the stroker kit.
 
Why I said leave it alone unless you truly have the $20,000+ to spend to do it right.

Another factor for me deciding is Corvette Values dropped.
Pontiacs worth much more.

Never get your money back unless its a 1000 hp Racer.
What mainstream wants.

Or Ultra rare factory muscle.
 
the best solution from a performance perspective is to do the required calculations to select the longest length connecting rod and the lowest weight piston,
of a decent design that will reduce the reciprocating mass significantly more.
the tall deck has a 10.2" deck height, a good dual plane aluminum high rise intake manifold will tend to provide the best compromise if you use a low compression and mild cam duration,
while it might seem like a waste of time, now, reading the links and sub-links will provide a good base to work from, later and save you a great deal of wasted time and money

you have a choice, you can slap the components you own together, now and live with what you have built regardless of the results ,
or you can put some real thought into making the result perform and carefully select parts and significantly boost power...
yes that routes more expensive up front,

but in the long term it tends to get better results and cost LESS.
common BB CHEVY piston compression heights are
1.270"
1.395"
1.520"
1.645"
1.765"

remember the blocks deck height, minus the piston pin height minus 1/2 the crank stroke will equal the required connecting rod length
OR
the blocks deck height, minus the connecting rod length, minus 1/2 the crank stroke. will equal the required piston pin height

if you wonder why I suggest using SCAT (H) beam style cap screw connecting rods vs stock or most (I) beam designs this picture should show the increased cam to connecting rod clearance

After market performance ,big block connecting rods come in several common lengths
0704ch_15_z+chevy_big_blocka.jpg

6.7-6.8"

https://www.summitracing.com/parts/esp-67003dl19/overview/make/chevrolet

https://www.summitracing.com/parts/cpi-u16230/overview/make/chevrolet

https://www.summitracing.com/parts/sca-6670022a/overview/make/chevrolet

https://www.summitracing.com/parts/sca-6680022a/overview/make/chevrolet

https://www.summitracing.com/parts/sca-6680022/overview/make/chevrolet





0704ch_14_z+chevy_big_block+.jpg

notice the pin height in the pistons pictured above allow a longer or shorter connecting rod length

hrdp_0704_59_z+piston_tdc_diagram+.jpg

heres a selection of commonly available big block chevy connecting rod lengths

bbcdht.png

pinht1.png

pinht2.png


https://www.uempistons.com/index.php?main_page=calculators&type=deck

https://www.uempistons.com/index.ph...n_comp&zenid=a0b4d1c0899b781e5a1cffb2fe0afe21

http://garage.grumpysperformance.co...in-height-compression-height.5064/#post-69254

your going to want the longer length and 150%-200% stronger aftermarket connecting rods with the much stronger 7/16" ARP rod bolts if your building a tall deck BBC engine,
so if your trying to build the best combo, you should select the longest and strongest connecting rods that allows you to select an off the shelf compression height piston to save money,
keep in mind head gaskets come in head gaskets come in .010 steps from about .020-to-about .80 and blocks generally measure 10.223 if that O.E.M. block has not previously machined, try too get the quench in the .040-.044 range,
you can get the piston thats compression height is .010-.015, .020 , .025, below or above the deck height, and with a matched head gasket get the quench correct after measuring the deck height, and compression height.


496cmph1.png

496cmph2.png



Diamond_12711_nitrousdome__25621.1432240797.png

I recently helped one of the local guys assemble a 496 BBC 4.25" stroke
engine using 6.385: SCAT rods with 12.7:1 pistons thats being built
I watched him start to install the first piston with the dome facing the lifter gallery, or upper side of the cylinder... I waited until he had started to install the connecting rod cap on that first rod and asked him to rotate the crank to TDC I handed him a bridge and a dial indicator
66962.jpg

66797.jpg


https://www.uempistons.com/index.php?main_page=calculators&type=deck


https://www.uempistons.com/index.ph...n_comp&zenid=a0b4d1c0899b781e5a1cffb2fe0afe21

http://garage.grumpysperformance.co...in-height-compression-height.5064/#post-69254

and asked him to verify the deck height.....honestly I had a real hard time not laughing.....I think most of us realize that we all made similar mistakes.... no harm done (YET).
after a few seconds, I suggested he check the spark plug clearance with the head just laid on the block with an old head gasket...yeah, he caught the mistake then!

enginerebuild128.JPG


https://mobiloil.com/en/article/car...w-to-assemble-an-engine-part-2-the-bottom-end

http://garage.grumpysperformance.co...ed-holes-in-bearings-shells.10750/#post-53298

https://mobiloil.com/en/article/car...w-to-assemble-an-engine-part-2-the-bottom-end

http://garage.grumpysperformance.co...d-side-clearance-dont-assume.4690/#post-12702

http://garage.grumpysperformance.co...nk-durring-short-blk-assembly.852/#post-39417

http://www.hotrod.com/articles/0901phr-less-expensive-big-block-chevy-engine/

http://garage.grumpysperformance.com/index.php?threads/measuring-rod-and-pin-heights.3760/#post-9968

http://garage.grumpysperformance.com/index.php?threads/deck-height-problems.3048/#post-8048

http://garage.grumpysperformance.com/index.php?threads/quench-squish.726/#post-1023

http://garage.grumpysperformance.com/index.php?threads/sealants-and-threads.805/#post-71928

http://garage.grumpysperformance.com/index.php?threads/head-gasket-related.1859/#post-50617

http://garage.grumpysperformance.com/index.php?threads/bearing-clearances.2726/page-2#post-75256

https://www.uempistons.com/index.ph...e=deck&zenid=823ce2c9e2ffa691864d832c10107df0

https://www.uempistons.com/index.php?main_page=calculators&zenid=823ce2c9e2ffa691864d832c10107df0
 
Last edited:
Grumpy.........I just spent a couple hours reading previously posted linked info!
I thought I had a good grasp on the concepts involved.
I come back into this thread and as usual ,
by the time I had read through several links and sub links.
I find that theres a couple dozen more posted links and Lord knows how many related sub-links?
Yes I do remember reading the "Down the rabbit hole thread"
but by the time I catch up, on my reading and buy the tools I think I now need...
Ill be too old , and too broke too build any engine!:D:)
yes I'm kidding, I appreciate the depth and details!
almost every time I start to post a question, a few minutes later,
I find a link that answers it.
or I get side tracked thinking about a separate new question.
 
Last edited by a moderator:
Ah, more reading. You are an evil retired English teacher, aren't you?
I am truly thankful that you have taken the time to aim me in the right direction.
Now I must absorb as much of this knowledge as my pea sized brain can.
I will keep you updated on my project as it comes together.
I have a good picture in my head, I just have to make it happen.
I have been searching the interweb for pricing estimates.
So far, I don't like it... but you cant take it with you, right?
 
Last edited by a moderator:
One thing that I've learned over the years is that you don't have to stick within the manufacturers line to accomplish your end goal. By that I mean you don't have to use ford parts just because you are dealing with a ford. There are tons and tons of engines made with different length connecting rods and pistons. By the time you get to changing all these items around you'll want to get the reciprocating assembly balanced as well. Those 427 tall decks are popular in agricultural applications as were the 366 cu. inch engines. I see them and components for sale all the time. It used to be that if you wanted a top notch small block you could get one out of a combine, complete with "pink" rods.
 
yes theres zero doubt you can build some of the more common SBC and BBC engines with either a mix of O.E.M. and and aftermarket components,
BE AWARE NOT ALL POTENTIAL PARTS COMBOS ARE COMPATIBLE
or go with just aftermarket components through out.. It should be obvious that you'll need to do some research , and calculations on,
rod length, bearing clearances, compression height, compression ratio, quench, and valve train geometry,intended port flow, valve lift,
and carefully verify the clearance , and valve train geometry issues before ordering components, and during the actually assembly.
 
Back
Top