From everything that I've heard, 69 was sort of a unique year, all engines had 2" exhaust systems. Even the BB's, with 2 and 1/2" exhaust manifold outlets, were necked down to 2".
Corvette Central lists a 2 1/2 system for a '69 and says it's for 427s.
I realize this doesn't necessarily mean it is factory correct.
So, what is the real scoop?
I know some C3s must have come from the factory with 2 1/2 pipes as their are 2 different factory parts for the brace under the tranny mount. and one is for 2" and the other for 2 1/2" pipes.
The real scoop is that some C3's had 2" and some had 2-1/2". For example, in 68, all small blocks had 2", except for those equipped with off road exhaust, and all 427's had 2-1/2". In 1970 the Lt-1 350 had 2-1/2. From what I have been able to find from my research is that in 1969 all engines were equipped with 2", no exceptions. This is supported by info from the GM Corvette Parts Catalog(1953 to 1980) and the NCRS 1968-69 Corvette Technical Information Manual & Judging Guide. It appears that a 68 BB system is a direct bolt on for the 69 BB with the addition of 2-1/2" clamps. The 69 SB might also be done using a system from another year, say a 70 LT-1. It also appears that one could use a combination of GM parts to install a 2-1/2" system on a 69, BB or SB if he desired to do so. The aftermarket folks for the most part are reproducing and can make them to fit most any application they want, so wouldn't want to give much credence to them being an authoritative source. The GM parts catalog lists two transmission clamps(mounting bracket) for 69's, a 3853723 for manual and a 3952739 for auto.
Last edited by gkvetteuno; 03-08-2007 at 03:31 PM.
At the moment don't remember about all the other 68's but my original owner 68 327/350 4-speed M21, 3:70 rear, and no ps or pb has 2 1/2 inch exhaust. My build sheet does not have off road exhaust on it and neither does my order make up sheet from the dealer. The original exhaust manifolds do not have 2 1/2 outlet, the front exhaust pipes begin as 2 inch and enlarge to 2 1/2 a few inches from the pipes exhaust flange. The replacements I put on years ago are the same as the originals. I converted my 70 Vette to the same 2 1/2 inch system about 18-19 years ago. Had to change the exhaust support bracket at the rear of the transmission from the 2 inch piece to the 2 1/2 inch bracket.
Corvette Store
'69 factory exhaust (non sidepipes)
