Joe - Exhaust manifold part question

[Joe L.]

Re: Joe - Exhaust manifold part question

Tim-----

The '942' manifold often has the additional casting number of 3797902 or '902' on them. However, I've never seen a no-gen-boss 3797901. There might be some, though.

An interesting thing is that I've never been able to find any indication that the 3797942 manifold was ever available in SERVICE under that number or any other part number. From all that I can tell, it was a PRODUCTION-only item.

[Joe L.]

Re: Joe - Exhaust manifold part question

Tim-----

The '942' manifold often has the additional casting number of 3797902 or '902' on them. However, I've never seen a no-gen-boss 3797901. There might be some, though.

An interesting thing is that I've never been able to find any indication that the 3797942 manifold was ever available in SERVICE under that number or any other part number. From all that I can tell, it was a PRODUCTION-only item.

[Elm Zobens]

Re: Joe - Exhaust manifold part question

Thanks Jim, Joe and Tim for your responses!
I do have a couple more questions-
Would there be a noticable advantage in using the 3797901 manifolds and running a 2.5" exhaust all the way on my ZZ3 motor instead of using the factory L-46 2" manifolds and either running my existing 2" exhaust or going to the 2" to 2.5" 'Flared' exhaust?
To me it would seem the flared exhaust set-up would be of minimal benefit since the main restriction would be the 2" manifold and I'm not sure going from a 2" manifold to a 2.5" pipe would really improve much.
On the other hand, would a full 2.5" exhaust from the manifold on give me a noticable improvement to warrant the $500 or so investment in exhaust?
(my current 2" aluminized system is 2 years old and looks brand new).
Any suggestions or advice?
Thanks!
Elm.

[Elm Zobens]

Re: Joe - Exhaust manifold part question

Thanks Jim, Joe and Tim for your responses!
I do have a couple more questions-
Would there be a noticable advantage in using the 3797901 manifolds and running a 2.5" exhaust all the way on my ZZ3 motor instead of using the factory L-46 2" manifolds and either running my existing 2" exhaust or going to the 2" to 2.5" 'Flared' exhaust?
To me it would seem the flared exhaust set-up would be of minimal benefit since the main restriction would be the 2" manifold and I'm not sure going from a 2" manifold to a 2.5" pipe would really improve much.
On the other hand, would a full 2.5" exhaust from the manifold on give me a noticable improvement to warrant the $500 or so investment in exhaust?
(my current 2" aluminized system is 2 years old and looks brand new).
Any suggestions or advice?
Thanks!
Elm.

[Joe L.]

Re: Joe - Exhaust manifold part question

Elm------

I don't think that you'll notice much difference with the 2-1/2" exhaust, regardless of whether you go 2-1/2" all the way, including manifolds, or if you use just the 2-1/2" pipes. Either way, I don't think that they'll be much difference over the 2" all the way. For example, GM rated the 1967 base 300 hp engine the same regardless of whether it had 2-1/2" exhaust (with manual trans) or 2" (with Powerglide).

Another thing to keep in mind: ALL 1969 Corvettes had 2" exhaust------from base 350 to ZL-1.

[Joe L.]

Re: Joe - Exhaust manifold part question

Elm------

I don't think that you'll notice much difference with the 2-1/2" exhaust, regardless of whether you go 2-1/2" all the way, including manifolds, or if you use just the 2-1/2" pipes. Either way, I don't think that they'll be much difference over the 2" all the way. For example, GM rated the 1967 base 300 hp engine the same regardless of whether it had 2-1/2" exhaust (with manual trans) or 2" (with Powerglide).

Another thing to keep in mind: ALL 1969 Corvettes had 2" exhaust------from base 350 to ZL-1.