High Performance SBC identification and maintenance

L

LLave

Member
Hey guys,

I just scored a new project its a 260Z with a small block and a T5. The motor is of unknown specifications but it pulls HARD. Runs pretty well but needs a tune up. Here is what I now about it. The block is supposedly out of a truck. It has center bolt valve covers. An Edelbrock air gap intake, Edelbrock carb, headers, a fairly big sounding cam, timing gears, MSD HEI distributor which i am told was just stabbed in at 6 degrees. Displacement unknown, heads unknown, ect ect ect.

I would like to identify what exactly I am working with and catalog the parts. Where is the best place to start?

I am told the motor was never really fine tuned and dialed in. Coming in late in the game like this, where do i start? I would like to do a through tune up. I know valve springs can wear pretty fast on a high performance SBC. How do i check them out and insure they are good? I have always owned very mild SBCs and this one definitely spicy. Can you direct me toward any basic tune up information for high performance motors? I want to do it right but I do not want to tear the motor down.

Thanks,
-Mike
 
Well.... It does not matter much now. The motor let go, gave up the ghost. Pieces of piston skirt in the oil pan. I did find out that the heads are obviously ported, the intake gasket matched, that may explain why the motor seemed to perform so well. I am trying to decide what to do next. I am looking for the most cost effective way to get a motor of at least equal performance to the last, while being tough as nails. Either rebuild that block, or purchase a short block and bolt those heads up, or bite the bullet and purchase a long block. I am unsure at this point.
 
I can give your several well proven combos, that have lasted for years in many cars that produce 450-550hp, but Id be forced to point out that any stock production block, or rotating components is a poor starting point if your realistic horsepower goals exceed about 550hp, as most production blocks, rods,pistons,cranks, even with added splayed main caps are highly stressed, by that point. stress is cumulative and while a block may last for many years on an engine thats capable of making over 550hp, but one that rarely taken to its full potential, a stock production blocks a poor choice on a true high hp application.
as a general rule the secret to a durable combo,thats not going to be excessively expensive to build, with impressive power for street use is in building the largest displacement that you can afford while designing the combo to maintain the lowest rpm and stress possible, at the horsepower levels, you want. this usually results in compromises, but the common result is a sbc in the 383-407 displacement range

reading material.....keep in mind theres a huge amount of info in the links and sub-links

http://www.nastyz28.com/sbchevy/sblock.html
http://outintheshop.com/faq/casting/castings2.html
http://www.thecamaro.com/Decoding/Chevy-Engine-Code-Decoding/
http://garage.grumpysperformance.com/index.php?threads/links-to-casting-numbers-and-info.632/#post-55259
http://www.chevyhardcore.com/news/reference-chevy-engine-block-casting-numbers/
http://chevellestuff.net/qd/engine_stamp_numbers.htm

http://www.mortec.com/bbc.htm

http://www.gearheadgeek.com/ghgj/in...neral-chevy-data/chevy-head-casting-s?start=1

http://www.nastyz28.com/gm-chevy-codes/chevy-engine-codes-suffix-13.php

http://www.chevyhardcore.com/news/reference-chevy-engine-block-casting-numbers/

http://outintheshop.com/faq/casting/castings2.html

http://www.chevy-camaro.com/chevy-camaro-engine-codes.asp

http://corvettec3.ca/partsman.htm

http://www.thecamaro.com/Decoding/C...ock_chevy_intake_manifold_casting_numbers.php

http://www.mortec.com/castnum.htm

http://www.holisticpage.com/camaro/parts/head.htm

http://www.mortec.com/castnum.htm

http://www.fastnuf.com/bbccastingnumbers.html

http://www.nastyz28.com/bbcmenu.php

http://www.nastyz28.com/sbchevy/sblock.php

http://www.geocities.com/meanracing/Blo ... ation.html

http://www.vehicleidentificationnumber.com/

http://www.chevyhardcore.com/news/reference-chevy-engine-block-casting-numbers/
castnu1.jpg

castnu2.jpg

castnu3.jpg

castnu4.jpg

castnu5.jpg


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From the bit of reading I did today, it seems that it is almost cheaper to buy a complete short block. I mean, by the time I get my block completely preped and machined, it is real close to the cost of a short block from Summit.
 
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