Hi everyone
I have a 68 cutlass s with a 350 in it single exhaust. I'd like to start tracking down parts to convert it to dual exhaust. Can some one explain manifolds? I have found a pair of x y? close to home but not sure what that means! If I understand correctly I can just use my current manifolds remove the y pipe that joins the two into one and run straight from each side? I've read that the x y have the wanted crossover for better exhaust flow? Will the x y's fit my small block?

Any light on the subject appreciated

Thanks
cola

 

I'm not an expert, but I don't think they'll fit. Those are the dual exhaust big block manifolds for 1968. If the price is right, you might snag them for trade stock though as there is good demand for them. I think your only option is to remove the crossover pipe and weld up a block off plate. You can keep a few inches of the crossover pipe and either pinch it off and weld it or make a disc to put in the opening and weld it on. I'm pretty sure that's the only dual exhaust option for small blocks with cast iron manifolds. John

 

Exhaust port spacing is identical between small block and big block heads, technically they would fit the heads, whether they would fit without interference on a small block in your Cutlass is a question I can't answer. The x and y manifolds don't have a crossover, they are each individual and are designed for big block heads, and are supposedly more desired by collectors and engine builders.

 

Big block exhaust manifolds will NOT fit ...the Pass. side will have clearance issues with the Oil Filter housing...Olds did not make a " true " dual manifold for the 350, so cap the crossover and you will be fine.

Danny

 

W and Z manifolds from the 69-72 big block A-bodies are much larger than others (due to the separate internal passages) and will not fit a small block due to the interferences noted above. Other big block manifolds WILL fit on a small block. For example, some have used the RH manifold from an early 70s Toro on small blocks.

 

You should just go with a set of headers, even cheap ones will sound better than the manifolds. and its less work.

 

Hi everyone and thanks for the reply's
70Wcars I see what you mean, I was under there today and it does look tight.
I think I'll go with your suggestion with capping off the y pipe and running the second set of pipes from the manifold back.

Thanks
cola

 

i did the capping off and keeping the manifolds, i could not justify the cost of Hooker Super Comps, as they are the only headers i was able to find for my car. here is a few pics