My 144 has a B20, single Weber downdraft, and IPD headers.

My 142 has a B18, dual SUs, and one-piece cast iron intake/exhaust manifold (dual exhaust ports).

My plan is to swap the motors, ending up with the B20 in the 142, and sell the 144 with the B18. I'd rather run the SUs on the B20, but I'd like to keep the headers on it. Is there an intake manifold that would allow me to do this? Is there an exhaust manifold that would allow me to set up the Weber on the B18 without having to put headers on it?

Is my desire to keep the headers on the B20 completely pointless? If it's not going to help the B20 breathe any better, I'll just swap the whole carb/exhaust systems between motors. Sorry for the rambling questions. And thanks for any input.

TF