Would anyone know if the rally 350 exhaust listed on the Gardener website is the same as a 70 pace car 350 system
it has a 2-1/4 head pipe?

 

Likely not. The 70 Pace Car Cutlii were just Supremes. The Rallye 350 used the same exhaust as the W31, except for the tailpipes with trumpets.

 

OK,so I'll have to buy manifolds also.
i'm pretty sure you're wrong because they use the block off plate on the dual exhaust so the manifolds are probably exactly the same!

 

I didn't say that the manifolds were different. All 350 motors in a given year, including the W31s, used the same manifolds. The PIPES and MUFFLERS are different.

 

if that's the case, then the answer to my original question should've been "yes" not not likely.
correct?

 

The key difference would be if your pace car has a cutout bumper or not. Rallye 350's had cutout rear bumpers for duals with trumpets.

 

No cutouts shown in the pictures from the other thread:

https://classicoldsmobile.com/forums...ce-car-170485/

 

Wow that was Fast cars here!

 

The Cutlass Y74 cars got a straight bumper and turn-downs, as did EVERY SBO-powered car except the Rallye 350.

 

dual exhaust was an option on pace cars along with the cut out bumper

 

Again, there is NO RPO code for the cutout bumper. RPO N10 dual exhaust did NOT include the bumper on 350 cars and it was not available as an option by itself. The 442 versions of the Y74 cars got the cutout bumper and trumpets because they were 442s. The Cutlass Supreme cars with 350s did not. SX Cutlass Supremes with 455 DID get the bumper and trumpets.