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yeller
12-04-2011, 03:02 PM
Hoping there are some Chevy guys here that can answer a few questions.


I'd like to end up with a 502 EFI in my boat. It may end up being bought in pieces, but I'm not familiar with the different generations.

The questions I have are:

Are the different generation parts interchangeable? I doubt I'll end up buying a bare block, so my main concern is the heads and intake.

Are all 502's roller blocks?

Is one generation more desirable than the other?

Will my 496 HO exhaust work on the 502? I've been finding conflicting information on this. How about the 496 coupler?

Any help would be appreciated.

Carl C
12-04-2011, 03:44 PM
Exhaust is close but no cigar.

Pismo
12-04-2011, 04:59 PM
1996 was the year the gen vi introduced with the roller setup standard. Gen iv and v do not have roller but can be modified to have roller. Another big thing is the fuel pump. Gen iv has ability to have mechanical, gen vi not. Get a gen vi. Coupler should work on all.

f_inscreenname
12-04-2011, 05:17 PM
I know between the Mark 4 and Gen 5 (don't know about gen 6) fuel pump, heads, crank are different and the flywheel has a slightly different balance.

gcarter
12-04-2011, 08:29 PM
Mike, I was under the impression that the Gen VI blocks will accept any of the heads.

Pismo
12-04-2011, 08:59 PM
http://www.chevyhiperformance.com/techarticles/4567_chevrolet_big_block_engine_generations/index.html

http://www.s-series.org/htm/tech/GMPerfParts/099-104.pdf


Here is some info

The fuel pump boss is back! sort of...

f_inscreenname
12-05-2011, 12:01 AM
"Mike, I was under the impression that the Gen VI blocks will accept any of the heads."

Anything is possible but if you ever put them side by side it would give you pause. Water passages are not the same. That's why they say you can use a special gasket but I would only do it if I had some bad a$$ after market heads that I couldn't get rid of.

biggiefl
12-05-2011, 03:10 PM
The 502 and 454 can use the same exhaust and intake manifolds and I think the heads. I had a 502 aluminum/brass inlay intake on my Baja. A quick lookup at GLM or CMI would show you if the 496's have the same part numbers.

RickSE
12-06-2011, 10:12 AM
I still wonder why marine folks never seem to be interested in the GM DRCE blocks, especially the aluminum version.

DRCE (http://www.gmpartsdirect.com/performance_parts/store/catalog/Category.jhtmlCATID=1323.html)

zelatore
12-06-2011, 10:49 AM
Rick, I'll guess that's because Olds doesn't readily spring to mind when you think boat power. And, from the link you posted:

Oldsmobile DRCE blocks and cylinder heads are not interchangeable with Chevrolet components

So, while you can probably build a killer motor out of this stuff, I have to think the selection is smaller and the price higher than a standard BBC.

Might be cool for the 'alternative' crowd, but I can't see it being a popular choice for the average builder.

yeller
12-06-2011, 02:09 PM
Thanks for the info everyone. That will help my search.

Carl, do you know for sure that the 496 exhaust can't be used? I have read that they can with some minor modification, but I haven't been able to find out what that modification is.

RickSE
12-06-2011, 02:15 PM
Don, the DRCE is a Chevy. This is just the GM Corporate drag race engine, Drag Race Competition Engine. You have to use DRCE heads but the block accept all big-block Chevrolet internals. The heads are basically BBC with improvements.

I guess some boat guys are using them. http://uk.boats.com/accessories/keith-black-oldsmobile-drce-11532862/

handfulz28
12-06-2011, 06:32 PM
[ QUOTE]Carl, do you know for sure that the 496 exhaust can't be used? I have read that they can with some minor modification, but I haven't been able to find out what that modification is[/QUOTE]

The exhaust port and bolt hole location are identical, as proven by the fact they all use the same exhaust manifold gasket. So the 496 manifolds bolt to any standard big block head and vice versa.

The difference is the riser outlet location. The standard 496 w/6" riser would probably be a little lower on a 454/502 vs the 496. There should be enough "play" in your standard 4" exhaust hose to accommodate the slight mismatch between riser outlet and exhaust tip.

I think Carl had a problem because the 525 heads have raised exhaust ports, so the exhaust tips needed to be raised.