Phil's79

Getting ready to set up the exhaust system on my 79 and measured the inside diameter of my exhasust maniflods and they were 2 1/2". Huh?? Casting numbers are LH 3787901 and RH 3797942. I think I have traced the RH to a 63 vette. Can someone verify this and help with the RH orgin. I guess this also means that stock configutation will be difficult since the systems are for 2" manifolds. I thought about dualing it out with cats but may not pass emmissions check. Anybody got any suggestions?

Bob K

"Casting numbers are LH 3787901 and RH 3797942. I think I have traced the RH to a 63 vette. Can someone verify this and help with the RH orgin. "

As per my NCRS pocket guide:

3797942 was both left and right sides:
'63 327/360 (L/H)
'64 327/375 (L/H)
'65 327/375 (L/H)
Or
'64 327/300 w/MT & AC (R/H)
'65 327/365 w/AC (R/H)

3797901 was used on:
'62 327/300,340,360
'63 327/300 w/MT (L/H)
'63 327/340 (L/H)

good Luck with everything

bBb K.

Phil's79

Thanks for your help

L79vette

uhh.. suggestions for what? How to get a '79 to pass emissions with 2.5" manifolds?

Depends a lot on the laws where you are. If they are strict, they will require the A.I.R. to be active, and those manifolds don't have provision for the air injection tubes. Where I am in Colorado it wouldn't matter what numbers it blew on the sniffer, you have to have all the original emission controls back to '75.

If you tell what numbers you need to hit and what the rules are, someone might be able to help you figure out how.