Are the (RH) Cutlass 350 exhaust manifolds the same/ similar/interchangeable for 68-70 and 71, 72? ( I assume they are, less slight casting number location differences...) ...thanks

 

1964 thru 1976 or so all used the #3 or #4 RH manifold. 2-bolt exit is down and aft at about 45 degree angle. Interchangeable.

After that came the #5? and similar tiny castings for 307's or 260's, all these sport a 3-bolt exit flange pointing straight down.

 

what is the difference between 350 1968-72 #3 RH and a #4 RH (is it the daul exhaust?)

thanks

 

Once again, Olds never made a dedicated dual exhaust manifold for the small blocks in a RWD application. All factory SBO dual exhaust cars (including W-31s) simply had a cap on the passenger side crossover hole.

 

The only difference I can discern is the 6-digit casting ID and the large "3" or "4".

Otherwise identical and interchangeable.