2 1/2" exhaust w/ Auto - C2

[Ryan Clark]

I have a general question. From 63 to basically the mid seventies, did any Small Blocks cars with Auto Transmission come from the factory with 2 1/2" exhaust manifolds.

I know in '65 the manual trans cars got 2 1/2" while the Auto cars got 2".

Thanks
Ryan

[Duke W.]

Re: 2 1/2" exhaust w/ Auto - C2

All 250 HP and 300 HP with Powerglide from '63 to '65 were equipped with 2.0" manifolds and exhaust pipes.

After '65 all SBs had 2.0" manifolds, but PG continued with 2.0 inch pipes, and manuals all had 2.5" pipes, all horsepower ratings through '67.

Duke

[Joe L.]

Re: 2 1/2" exhaust w/ Auto - C2

Ryan----

Duke's info for mid year exhaust is correct; for the 63-67 period no auto trans Corvettes were equipped with 2-1/2" exhaust. However, for the C3 period, that changed.

For 1968, ALL Corvettes received 2-1/2" exhaust, regardless of engine or transmission. No 1969-72 small block with automatic tranmission was equipped with 2-1/2" exhaust, though.

Beginning in 1973 and continuing through 1974, L-82s were all equipped with 2-1/2" exhaust, whether they were automatic or manual transmission.

No small block after 1965 had 2-1/2" outlet exhaust manifolds, though. 1965 was the last year for 2-1/2" outlet exhaust manifolds on any small block engine.

[Jerry M.]

Re: 2 1/2" exhaust w/ Auto - C2

66 and 67 big block powerglide's had 2.5" exhaust

[Ryan Clark]

Thanks *NM*

[Joe L.]

Re: 2 1/2" exhaust w/ Auto - C2

Jerry-----

Yes, with one exception, all 1965-74 big blocks were equipped with 2-1/2" exhaust regardless of tranmsission or engine horsepower rating. The exception was 1969 Corvette big blocks. ALL 1969 big blocks were equipped with 2" exhaust, including L-88 and ZL-1. The exhaust manifolds were 2-1/2" outlet, as were ALL big block exhaust manifolds, but the forward exhaust pipe had a reduction section to transition the exhaust size down to 2".