OK, here's my next issue: I found a crossmember with dual bump outs to fit my 77 Cutlass and am now trying to find exhaust to fit it. I found a guy that can bend up a system that will fit up for a 74 but will that fit up with my 77 manifolds with the crossover blanked off or do I need to find a set of 74 exhaust manifolds. He said his set is 2" on the drivers side and 2.25" passenger side. I have seen aftermarket manifolds that are 2.25" both sides, but i'm not sure yet if he can bend up 2.25" for the drivers side. I'm trying to avoid a muffler shop because they will have to put Cats on it. I know that the manifolds I have on it now have a 2" 2 bolt flange on the drivers side and a 2.25" 3 bolt flange on the passenger side.

 

It will fit fine with the 74 crossmember in place.


LH manifold will be no problem. 75-later RH, the exit angle to the headpipe is much different from 74-earlier. Earlier manifold will make the job easier if the pipes are already bent for 74 but if you have welding and fabrication skills making it fit the 77 manifold won't be hard.

 

Thanks, I wasn't sure how similar the exit angles would be from year to year and found it odd that one side was 2" and the other 2.25". But according to everything I've seen there are no Olds 350 true duals. They all had the crossover pipe or it was capped if it was the factory option for duals.

 

That's right. Factory installed a gasketed metal cap on small-block dual exhaust jobs. Check some of the Olds vendors, I'm pretty sure that cap is reproduced.


Different size exhaust pipes are nothing odd on an Oldsmobile! I think they did it for cost reasons more than anything. The RH exhaust was sized to flow both cylinder banks and that way they could still use the RH single exhaust for a DE system.

 

I can agree with that. They are costing me right now!