Thank you Joe Lucia!!!!

**Joe L.** · June 9, 2008, 01:11 AM

Re: Thank you Joe Lucia!!!!

Originally posted by Greg Euston (49104)

The detailed information you sent me was a big help Joe!!!!!

I purchased my Vette as is, i have done no modifications to the engine, drive train or any other part of the car. I'm sorry i can't give you more detailed information about the internals of the engine, all the work was done before i purchased the car. The Engine # matches the Vin and Chassis # 's. When ever and who ever did these modifications they were done a long time ago from what i can see.

I'm restoring my Vette as close as i can to NCRS standards??

The accelerator cable on my Vette looked OK and functioned fine, but i thought it might be best to replace it any way so i have a new GM cable ready to fit.

I think the engine still has the LS5 Bottom End, but i'm not sure. Either am i sure about the Cam Shaft. I will do a compression test on the engine and that will give me some answers i suppose?? The heads are Cast Steel, not the original aluminium type unfourtunatly!! I have had the Intake Manifold off the engine and wrote down all the numbers i could see and markings, but i have lost that piece of paper, the heads had GM - HI - PER cast into them and hudge rectangle ports, i remeber that.

The intake manifold has Part # 3963569 on it and it is Aluminium.

I can't afford to return the engine back to LS5 spec, how are these modification going

to effect points deductions when i have the car judged??

All the best....

Greg...
Australia

Greg-----

First of all, a compression test won't tell you much about the compression ratio or anything else regarding the bottom end. So, while there are good reasons to run a compression check, it won't really provide this sort of information. The real "bottom line" is how does the car run? If it runs fine and you're happy with that, then there's really no reason to worry too much about what internal parts are in the engine.

The GM #3963569 manifold is pretty much guaranteed to be the one you'd have assuming the rectangular port heads, Holley carb, and stock 68-72 big block hood. There is NO other rectangular port, Holley flange intake manifold that will fit under a 1968-72 big block hood. None EVER made. By the way, the GM #3963569 was used for 1970 Chevelle LS-6 and 1971 Corvette LS-6 as well as 1970 L-78 used in Chevelle, Chevy II and Camaro.

As far as NCRS judging goes, you will take considerable "hits" for the non-stock intake manifold and carburetor. You MIGHT not be penalized for the heads since, externally, there's not too much difference between your original heads and the ones you have, assuming the heads you have feature tapered seat spark plugs. Otherwise, that might be a tip-off.

Assuming your bottom end is still LS-5, it might not be all that expensive to return it to LS-5 configuration IF you consider the value of the parts you would have to sell or trade. The 3963569 you have is worth more than the GM #3955287 cast iron manifold you need. The 3955287 was used on a lot of applications over the 70-71 period and is not rare and hard-to-find.

The GM casting #3993820 heads you need are also not really rare. Depending upon what heads you currently have installed, they may be worth more, about the same, or less than the ones you need. However, there should not be a huge difference between the value of what you have and what you need.

The Rochester GM #7041205 carb you need is quite rare and hard-to-find. However, configuration-correct Rochesters are not too hard to find, at all. So, you'd take a hit only for the wrong numbers and dates.

Thank you Joe Lucia!!!!

Thank you Joe Lucia!!!!

Comment