So I'm pretty sure I will skip headers in my Cutlass my goal is the repo y/z
or is it w/z anyway the higher flow manifolds.
two questions

1) Is there a 2.5 " exit manifold ? I thought I read somewhere there are more than one repop made . I only know of Thortons .
are Thortons 2.5 exit ?

2) Do the exits interchange as in do I need to buy the new manifolds at the time I do my exhaust or can I run whats on there and switch later?

thanks

 

My W/Z manifolds are 2" I had short adapters made to adapt 2.5" exhaust. Works great

 

Something like these from Ram Air Restoration?
http://www.ramairrestoration.com/cat...roducts_id=152



What do you mean by "interchange"? On the A-body manifolds, the SBO manifolds used on an SBO have their exhaust flanges in the same location as BBO manifolds installed on a BBO. Thus, the down pipes are the same.

 

Little off subject, but does anyone know the number and production info for the X / Z set? thanks.

thanks Joe, that was what I wanted to know. I should have stated production years, not info.

 

Yes, it is...

Do you really mean "X/Z"? Those would be the 73-74 BBO cars. The X/Y manifolds were used in 1968. The "W/Z" manifolds were used in 69-72. The 68 "X" manifold is casting no. 389269. The 73-74 "X" manifold is casting no. 412287. They are different manifolds.

As for production info, they were used on ALL A-body BBOs for the given year(s).