Firebird RAII Long Branch Exhaust Manifold Part Number Confusion
 

Need help trying to figure out exactly which casting part numbers applied to the 1968 Firebird RAII long branch manifolds. Lots of confusing info out there on various forums.

The options seem to be:
9794038/9794036 or
9794038/9794037 or
9794038/9797074

I have a rather old RARE catalog/handout that I picked up at the Ames Norwalk event 15 years ago which says their castings show the '69 Firebird RAIV p/n's 9794038/9797074, but that doesn't help me with '68.

Need help understanding what was correct for the '68MY RAII birds.

Thanks!

From the info I have your first two numbers are for 68.

I can’t find a 037 number anywhere.

Your last two sets of numbers are for 69 RA4 motors.

The top 2 might be the 'part' number? That's what I have for it. But I don't know if that is the 'cast' number on them. (never had one)

The right manifold could have the 037 'cast' number since it may be an assembly?

The RA IV were 9797074 & 9797075 part numbers.


:confused:

Agree with others that the 9794036 and 9794038 P/Ns are correct for 1968. I'm also noting that the LH P/N for '69 manifold did not change, but the RH P/N did.

It seems to me that most (if not all) '68 RH exhaust manifolds were equipped with a heat riser assy. I'm guessing, but could it be that the RH P/N changed for '69 due to the elimination of the heat riser feature?

Appreciate the responses. I think the as-cast versus machined/finished/assembled part number differences are at play here.

My drivers side manifold is cast -038. My pass side is cast -037. I'll try to post pics of them tomorrow.

In OE, the drivers side, once machined, is done and that's all you get.

In OE, the pass side, once machined, is then outfitted with the heat riser components and that may be what drives the machined part from -037 to -036.

This is somewhat supported when looking at the pricing on the attachment from Lamnas. Both of the RH manifolds for the round-port and D-port applications carry a price premium over the LH manifolds (which have no extra components attached to them).

In the aftermarket, the folks put the -038 and -037 part numbers in the castings (like I have), but the RH manifold is not machined for the heat riser components (the blobs of cast iron are there, just not machined). Perhaps "-037" applies to the as-machined part, but since GM never sold this in service we don't see it in the parts books. Only -036 shows up. And then that changed in '69 with the RAIV cars that have no heat riser pieces.

Wish I could see the OE drawings from back then...

Attaching pics of my manifolds. These appear to be correct for the '68 MY.