Exhaust Casting Numbers

[chevyaddict]

Does someone have a code book that would tell me if 3932461 with part #'s RH3 and RH4 are the correct numbers for 68 corvette exhaust manifolds?

 

[RalleyRed]

I've got a book here that shows numbers.....

.....3872765 for the left small block
.....3872778 for the right small block

.....3880827 LH big block
......3880828RH Big block

For the 68's

The numbers you listed are shown for all 3 years (70,71,72) of the LT-1's but only for the right side.

Along with the base motor in 72 listing shows both sides are the same number.

Rick

 

[chevyaddict]

Thanks! I probably would have purchased these in hopes of them being correct. Whew!!

 

[JohnZ]

part #'s RH3 and RH4

Those two markings are just casting pattern numbers - they don't mean anything in terms of buying replacements; the numbers given in the post above are the correct "casting numbers", which are what you need. The GM part numbers are different, but aren't shown on the part, and the parts were discontinued from the GM parts system many years ago anyway. You "hunt" for the parts by the casting number

 

[born2saw]

My book (Corvette parts interchange manual) shows different numbers (that seems to happen quite frequently).

For the 327:

Passenger's side:
Part number 3893604, Casting number 3932465
Also was used in 69-71 Corvette 350, 69-70 Impala 327/350, 1970 impala 400 2 barrel.

Driver's side:
Part number 3846553, Casting number 3846559
Also used in 67-68 Corvette 327 with A.I.R., 69-71 Corvette 350, 67-68 Chevy & GMC pickup with A.I.R., 67 Chevy pickup 283 with A.I.R., and 68 307 pickup.


For the 427:

Passenger's side:
Part number 3880834, Casting number 3880828
Also used in 68-69 Corvette 427, 70-74 Corvette 454, and 66-69 Impala 427, (425 hp only)

Driver's side:
Part number 3880833, Casting number 3880827
Only used in 68-69 Corvette 427

My Chevrolet by the numbers 1970-75 lists the same casting numbers on the corresponding parts.

Several local vette people swear by these books as helping them find Corvette parts at 'non-Corvette' part prices. As Chevy always tried to use whatever parts they had lying around this makes a certain amount of sense.

Hope this helps rather than confuses.

Good luck finding what you need.

 

[James Price]

Exhaust Manifolds

Check out www.nastyz28.com

They have a big list of identification numbers for Intake and Exhaust manifolds.


I too am looking for the correct manifolds for an 78 L82.

Jim

 

[JohnZ]

The Corvette Parts Interchange Manual is wrong for the 327 application. 3846559 was used on (some) Corvette applications from '64-'67, then again on (some) applications again in 1970 and 1971, but was not used at all in '68 or '69. 3932465 had only a one-year Corvette application - 1970 300 and 350hp engines without air injection.

There are lots of Corvette books out there, but most of them are poorly-researched and inaccurate when it comes to this kind of detail; the only publications that have it right are the NCRS Spec Guides and the (new) "Corvette By The Numbers" book by Alan Colvin.

The '78 L-82 used 3932461 on both sides, but the R.H. side had two A.I.R. holes drilled in it, and the L.H. side had four (same casting number, but the different machining treatments on the same casting created two different finished part numbers).

 

[born2saw]

JohnZ,

Alan Colvin states in his Chevrolet by the numbers 1970-1975 that 3932465 was used in Chevy passenger cars 350 ci 250 & 300 hp w/o A.I.R., passenger car 400 ci 265 hp and 1970 Vette 350 ci 300, 350 hp w/o A.I.R. It also has a note that "this manifold was also used in 1969" but does not specify the application. Did he change his mind in later books? This was an older(?) copy (copyright 1994) that came with my vette from the previous owner.

Would it be worth it for me to buy the latest Corvette By The Numbers? Or, I could always rely on the good people here at CAC!! I always try to find at least two different sources that agree before I spend any money.

Where are the NCRS specs guides available?

Thanks for the additional input.

P.S. We could always email this thread to Mr. Colvin at Corvette Fever Magazine and see what he says.

 

[JohnZ]

Alan is a colleague of mine (we're both Core Members of the CRG - Camaro Research Group, www.camaros.org), and his new "Corvette By The Numbers" book is specifically dedicated ONLY to Corvette parts usage, and is a terrific piece of work; you have to remember that the one you have is almost ten years old, and isn't specific to the Corvette. If you forward this thread to him, you'll get exactly the same answer shown above. His new book is available from all the Corvette resto parts houses and from major booksellers as well. In addition to "the numbers", it also has hundreds of photos and graphic illustrations of disassembled components to show the internal differences and how to identify the parts individually.

The NCRS Spec Guide (one edition for '53-'62 and another one for '68-'82) are available from the NCRS On-Line Store at www.ncrs.org.

If you have the Colvin book, the NCRS Spec Guide, the Assembly Instruction Manual, and the Chevrolet Chassis Service and Chassis Overhaul Manuals, you've got the basic beginnings of a technical library that will REALLY teach you about your Corvette (the generic manuals like Haynes, etc. are a poor substitute for the GM factory assembly and service manuals).

 

[born2saw]

Thanks JohnZ

My car came with a 1975 Corvette assembly manual (from Corvette America), an original 1974 Chevrolet Chassis Service Manual Covering Chevelle, Monte Carlo, Nova, Camaro and Corvette, an original 1975 Chevrolet Service and Overhaul Manual Supplement, and Chevrolet by the numbers 1970-75. I got the parts intechange manual 1968-1982 as a gift. My understanding is that these are the the correct Chevy service manuals for my car(?). From what I have seen, that is about $200.00 worth of books that were included in the deal!! I will take you up on getting a NCRS Spec guide. Any other suggestions for my library? I have about $80.00 in Borders gift cards to burn!! I was thinking of gettin a Chilton's or Haynes, but from your note I probably don't need them, but now I guess I should replace the Chevy by the numbers with a new Corvette by the numbers (by the way, Chevrolet by the numbers has hundreds of photos and graphic illustrations of disassembled components to show the internal differences and how to identify the parts individually also).

CAC rules!!

 

[JohnZ]

Sounds like you've got a pretty decent library going already! When you go to Borders, the new Colvin book is under ISBN #0-8376-0288-2, and it also carries GM Part Number 88960650 (the ONLY book not published by GM that carries a GM part number).

 

[jmp]

I've got a book here that shows numbers.....

.....3872765 for the left small block
.....3872778 for the right small block

.....3880827 LH big block
......3880828RH Big block

For the 68's

The numbers you listed are shown for all 3 years (70,71,72) of the LT-1's but only for the right side.

Along with the base motor in 72 listing shows both sides are the same number.

Rick

My book, "Corvette Restoration Guide" by Richard Prince gives the same numbers for the 68 as above.

The number 3932461 is listed, in my book, as being the right side for 1970 and 1971 LT-1s, the left side for early 1972 350/200s, and the left and right side for "Late 350/200 and LT1 350/255". However, it also gives a completely different number, 386711, for left and right side "LT1 350/255".

I looked at my 72 LT-1 and both the right and left side have the 3932461 casting numbers, but only the left side seems to have the holes (four of them) for the AIR fittings. But I can't go by what my car has because it appears to have been altered somewhat -- the AIR system isn't on the car and the AIR holes in the manifold are plugged.