C-3 Exhaust replacement

[John D.]

I seem to recall that I read some where an early 68 327/350HP manual with air had the 2 and 1/2 inch exhaust, increased from 2 inch just after the attachment flange. I read in the TIM that this was only on the 68 off-road package. Am I imagining things?

Thanks, John

[Jim T.]

Re: C-3 Exhaust replacement

My 68 original owner 327/350 has the 2 inch cast iron exhaust manifolds and the pipe that connects to the exhaust manifold starts out as two inches at the connection point and increases to 2 1/2 inches. It has never had a complete 2 inch system.

[Joe L.]

Re: C-3 Exhaust replacement

John-----

ALL 1968 Corvettes used a 2-1/2" exhaust system. No exceptions. However, all small block exhaust manifolds were 2" outlet, so the forward exhaust pipe was swaged down to accomodate this. The rest of the exhaust was 2-1/2", except for the tail pipe (the short section attached to the rear of the muffler). This section was 2".

All 1968 big blocks used 2-1/2" exhaust from the manifold outlet to the muffler. The tail pipes were 2", though, just like small blocks.

[John D.]

THANKS GUYS!!!! *NM*

[Craig S.]

Re: C-3 Exhaust replacement

Joe - my original exhaust on my 74 L82 is a distant memory since it is long gone and my L82 is in storage with the LS6 67 tripower with hooker sidepipes ready to go in.....but I do recall my original exhaust had mini resonators in front of the transmission crossover support, and I think it also had 2.5" to 2" as I recall. Was this practice used for a number of years? ...Craig

[Joe L.]

Re: C-3 Exhaust replacement

Craig-----

No, the resonators were used ONLY for 1974. You don't want to need them, either.

[Craig S.]

Re: C-3 Exhaust replacement

Joe - I was unclear in my ramblings, I was wondering if the "necked down" approach near the exhaust manifold was a common practice for C3 years. As far as my 74...well, it is destined to be a hybrid for a while, even though I have kept every last orignal piece except for the rear bumper cover which literally fell apart. The exhuast will be the hooker sidemount headers down the side of the car, with the LS6 up front and 4.11's in the back...Craig

[Joe L.]

Re: C-3 Exhaust replacement

Craig-----

The swaged down forward exhaust pipes were common among C2s and early C3s with small block and 2-1/2" exhaust. The "welded reduction" section forward exhaust pipes may have been used on some 70-74 LT-1 and L-82. From 1975+, I am unsure what the configuration was for the reduction section.

[Craig S.]

Re: C-3 Exhaust replacement=THX JOE! *NM*