Hi
I have bought my dream car Corvette C3 1973 L82 in February this year. I love it. Car runs great I have managed (with great support from all of you!) to deal with most of the problems. (Put probably same amount of money into it already:-)) This spring and summer I have drove 5.000 miles + without any problems. This is where my happy store ends. As probably most owners of C3 experienced - I also had to deal with extreme heat inside of the cockpit. Because my car was originally equipped with AC I decided to install new AC parts good with R134 and have my car shop to do the job. To make long story short - they have discovered that mounting brackets of compressor do not fit on the block. Furthermore figured that engine number has been filed.
The engine appears to be SB Chevy but how can I tell for sure? What year was it built? Were there any major differences that could affect proper selections of intake manifold, headers and camshaft in the future? I am not sure if there is a way to find out at all. I saw some numbers on manifold and block.... would anybody be able to help by looking at the pictures?

 

Welcome to the Forum!

Do a search on the internet for "engine block casting numbers" the casting number and date should get you in the ballpark.

With the engine and vin numbers gone, a few general photos of the engine might help the smart guys ID the block.

All V-8 engine block casting numbers are located on the top left surface of the flange formed at the rear of the block for engine flywheel attachment. V-8 casting dates are located on the right-hand side of the block, opposite the casting number.

Hope that helps, again welcome to the Forum.

 

Stock mounting brackets for C3 AC compressors are pretty much generic. A6 are the same for 68-75; R4 are the same 76-82. Your car should have the A6 compressor. What's on it? Post pics.

Decked posssibly? Have you checked the pad at the front off the right head?

Casting number will identify the block. Casting date will tell you when the block was cast. Same for the heads. Casting numbers and dates.

 

Thanks a lot for the idea. I´ll do that and let you know how it went!

 

I have A6 compressor, no doubt about that. From looking at the engine it seems that this particular block expects to have a compressor on left side (driver side) but Corvette specs show right side.
Yes I have checked pad in front of the right head it is smooth as baby skin.
When I get home from work I post some pictures for you to see.

Many thanks for swift replies to my post.

 

Ok I have done some investigation:
According to VIN my car was build in 1973
Block casting number is 3970010 and casting date H48. I have gathered this is often used block for car, truck and Vette applications 350 C.I.D. used in 1969 – 1979.
If my understanding of the structure of the casting date is correct - block was casted in 1978.
Intake manifold has number 3917610 - produced in 1967-1968 Z28, F, hirise
And finally heads have same number 333882 but different casting dates L123 and L63.

It is clear that engine is not original and put together from different parts.

I have seen application of this engine where AC is on left side of the block (I think it was Nova). could this be my case?

 

here goes picture where compressor should be mounted..http://forums.corvetteforum.com/albu...ictureid=90520

 

Your block has been replaced. Head casting dates of December 73 would have been for 1974 production.

Purchase the 73 assembly instruction manual (AIM). The AIM shows the complete installation of the factory AC system, including the compressor mounting brackets, stud, pullies, and correct belt routing.

Someone can correct me, but I'm not certain Chevrolet ever mounted the AC compressor on the driver's side of the engine.

 

Mike
It was normally mounted on driver side.
They got it right on ours by putting it on right w/ the rest of the A/C!

 

Those heads, although not the originals are identical in configuration to 1973 heads for both L48 and L82. Same goes for the block. There's no reason the A/C will not fit in the correct location.

 

Thank you all this has been great help to me.

I have maybe stupid question. Is it possible to swap heads from left to right? I found missing AC mounting holes on the opposite side of head - facing to firewall.

 

Yes that would do the trick.
pvana, you are a genius, none of us thought of that before you

 

350 heads should be the same. Accessory mounting holes should be in each.

 

Here is a drawing of the compressor mounting, from the Corvette Parts Book. Your 73 should mount the same as this illustration.



All air conditioned Corvettes built between 1964 and 1982, had the compressor mounted on the right (passenger) side of the engine. The only year Corvette that had the compressor installed on the drivers side, was the 1963.

 

Thank you very much this is good input!
I think I have figured out the problem - it is different water pump covering needed mounting holes. This engine seems to be put together from leftovers!
I have just ordered new pump from Eckler´s to be 100% sure. That should do the trick.
I have all things to install brackets now!

Thanks again!

 

gbvette62

OUT OF CONTEXT!
FIRST YOU NEED TO KNOW WHAT THE QUESTION WAS!


Mike
It was normally mounted on driver side (understood CHEVY V8 RWD).
They got it right on our(understood 68-82 CORVETTEs) by putting it on right w/ the rest of the A/C!


I realized after posting that it might need to be clearer for some. (Don't type & keeping it short.)

 

I'm not so sure. Your existing pump looks correct to me.

 

With headers, the mounting distance of the A/C compressor bracket will be altered compared to mounting with the stock exhaust manifold. You will need to space the bracket outwards to have the right spacing to work with the stock items.

 

Thanks for your observation. I was thinking the same.
I just have to make extra piece of iron :-) Ii have realized this when I put front bracket on - where I think it goes after new pump will be installed. there is no way to do it with old pump.