Buying Advice For A Chevy 383 Rotating Assembly

Thunderbolt

Well-Known Member
Thinking about rebuilding our 327 engine this winter, well the short block only, its a -68 or maybe newer.
It has sat like 20 years in the corner of the garage...
The cost of making it a 383 will be the same as a 327 (331) i think?

It had a loud dull knocking sound when it was replaced.
I think main bearing noise?

This will have to be shipped to Sweden, and i have a freight forwarder in Delawere i can use if i needed.
My funds are limited, and extra costs like shipping and customs will add...
...so where and what (brand/type) should i buy or avoid?

The measurments i will take care of, so its mostly where i can get the best deal im looking for,
maybe its so simple as Summit or Jegs?

I will use my Weiand 177 blower on the engine, E85 fuel, but can change to pump gas if they stop selling E85 localy. I guess i can go with cast crank and i-beam rods, but maybe should have forged pistons?

It will end up in our Impala SS -67.
 
a cast steel crank would be acceptable something like this rotating assembly,link below
be sure its a block that accepts the standard 350 main bearing crank size,
yes it costs more but BUT the quality of the steel and machine work tends to be far more consistent, so I generally advise use of a SCAT FORGED 4340 steel crank ,internally balanced for use with 6" connecting rods using 7/16" ARP rod bolts,
I've found the cost well worth the increased quality and lack of clearance issues

MATERIAL....................TENSILE STRENGTH.....PSI.
CAST
CAST IRON.....................APROX 75,000
NODULAR IRON................APROX 95,000
CAST STEEL...................APROX 105,000
FORGED
5140 forged steel.............APROX 115,000
4130.forged.....................aprox 123,000
4340 forged.....................aprox 143,000

CrankSpecifications-SBC01.jpg

and yes it will need clearance work, remember the heads you select, the port flow rates and combustion chamber
and valves size's will have a profound effect on the power the engine will produce and the tendency to run into detonation issues if your not running E85.
a 1967 impallas a heavy car, Id suggest you ger some 3.73:1 rear gears and if its an auto transmission a 3000 rpm stall speed converter to make the combo work.
read through these threads and sub links

http://garage.grumpysperformance.co...llecting-cylinder-heads.796/page-2#post-90819

https://www.hotrod.com/articles/ccrp-1209-eight-budget-sbc-head-shootout/

http://garage.grumpysperformance.co...-for-new-383-sbc-cam-instal.13109/#post-68326

http://garage.grumpysperformance.co...ing-a-383-sbc-combo-planing.12168/#post-58778

http://garage.grumpysperformance.com/index.php?threads/tbucket-engine-project-dart-shp.3814/

http://garage.grumpysperformance.com/index.php?threads/bits-of-383-info.38/#post-11767

http://garage.grumpysperformance.co...-on-building-a-383-sbc-stroker.428/#post-7304

http://garage.grumpysperformance.co...cu-sbc-in-vortec-head-build.12080/#post-57865

http://garage.grumpysperformance.co...y-in-building-a-good-engine.11682/#post-54682

http://garage.grumpysperformance.co...piston-to-bore-clearance-on-your-block.14251/

http://garage.grumpysperformance.co...earances-and-journal-surface.9955/#post-38385





keeping the low-cost theme build
set up with that supercharger and a decent cam like this
https://www.summitracing.com/search/part-type/camshafts?fr=part-type&SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=crower 00980


https://www.speedwaymotors.com/Premium-Small-Block-Chevy-Rotating-Assembly-383-Flat-Top-6-Inch-Rods,28520.html?sku=91510260&msclkid=53ad7077c4511df1d8002fe88f5da2a7&utm_source=bing&utm_medium=cpc&utm_campaign=SMI - Shopping (CSE) (Bing)&utm_term=4577404348890847&utm_content=All Products (Feb28_2020)
 
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I agree with Grumpy, need to check the journals to make sure it is the medium journal(2.45 in). There are 3 sizes 2.3, 2.45, and 2.65. 327s had either 2.3 or 2.45. SBC 400 was only one to have the 2.65 journal. With a 177 blower boost isn’t going to be high, I think a good quality hypereutectic piston would serve! JMHO!
 
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what you save initially, in lower price ,
will more than likely be made up in the cost of required machining and required balancing
you tend to get what you pay for, quality machine work and precision measurement and careful inspection processes take time and that costs money.
there is ALWAYS a compromise, made between quality and price
I learned that long ago,
“Quality is like buying oats. If you want nice, clean, fresh oats, you must pay a fair price.
However, if you can be satisfied with oats that have already been through the horse ...
that comes a little cheaper.”


thats why I generally suggest SCAT rotating assemblies
and having the required precision measuring tools, if you save $400 on the rotating assembly initially,
but need to spend $250 to get it balanced and $250 to get it polished ETC, what have you gained,
especially if its lower quality cast iron vs cast steel in a SCAT crank
remember in most case you still need a flex plate/flywheel and damper and associated bolts/fasteners etc.

every part you choose is a compromise , and may require changes,
that cost you in time, money or performance to some degree,
and almost every part will require a bit of fitting or clearance work,
or adjustment to fit and function to get the best results
if it drops out of the package and bolts together as it drops out of the package,
its almost certain its not functional to nearly its full potential

your job is to think things through carefully and make sure parts fit and function to their full potential,
little things like checking piston ring end gap, verifying bearing clearances, and ccing the heads and checking piston to valve clearance, degreeing in the cam and verifying the valve train geometry, polishing combustion chambers, getting a decent 3 angle valve job, MATTER!

as always it really pays to think things through carefully,

use a build sheet documenting all parts used, machine work done or scheduled and the costs and time required.
this will inevetably result in your having to do some research and ideally not skip over important steps like checking clearances, valve train geometry , parts selection and compatibility issues or lubrication and ignition system issues
break the build down into sections like the block and required machine work, the rotating assembly, heads and valve train, lube and cooling systems, matching the injection, carbs or intake manifolds selected, matching the headers and exhaust system, and of course matching the drive train gearing, differential gearing, tires and brakes to the intended usage.
all of these steps require some research to get the ideal results
related threads

http://garage.grumpysperformance.co...tion-of-crank-durring-short-blk-assembly.852/

http://garage.grumpysperformance.com/index.php?threads/scat-cranks-related-info.10930/#post-74729

http://garage.grumpysperformance.com/index.php?threads/a-few-basic-precision-tools.16344/#post-99006

http://garage.grumpysperformance.com/index.php?threads/types-of-crankshaft-steel.204/

http://garage.grumpysperformance.co...d-rod-orientation-clearance-issues-etc.16027/

http://garage.grumpysperformance.co...needed-for-383-sbc-assembly.16041/#post-96866

http://garage.grumpysperformance.com/index.php?threads/bearing-clearances.2726/page-2#post-87849

http://garage.grumpysperformance.co...g-with-a-local-machine-shop.14419/#post-74383

http://garage.grumpysperformance.co...ore-clearance-on-your-block.14251/#post-72471

http://garage.grumpysperformance.co...haft-journal-surface-finnish.2728/#post-72043

https://www.scatcrankshafts.com/rotating-assemblies/rotating-assembly-product-search/

http://garage.grumpysperformance.com/index.php?threads/precision-measuring-tools.1390/#post-68850
 
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Well, i also realized, while i was comparing prices, that i will need to buy a balanced assembly, so i passed on it.
 
you may benefit reading these threads
the sub linked info is priceless








 
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