I have a 312 with stock 454 MAG MPI’s 385hp and stock Merc exhaust manifolds.

Has anyone replaced the stock exhaust with EMI or Stainless Marine manifolds and risers on these engines?

Did you notice a difference in performance, RPM’s and top speed? Was it worth the extra $$$$$$?

Thanks

got 1 or 2 mph but thats not the real gain. You get rid of the wet gasket -if this leaks water enters your motor and boom! I happened to me. Motors $ , exhaust cheap only $2-$3 k..JIM