I have a 1967 400 car, the original motor is long gone... I sourced a 1977 Pontiac 350 and have installed it. However, when I try to install the down pipes from Pypes on the driver's side the pitman arm won't allow the down pipe to attach to the exhaust manifold.
I ordered the DGA13S, as that is the correct three bolt down pipes for a 1977 Poncho 350, a friend said to switch out to a straight pitman arm, and another said to find a set of early 2 bolt Poncho exhaust manifolds and order the Pypes DGF13S...
I tried the Pypes down pipes that they advertised would fit our FGFs. Because I live in CA they could not ship them to me here. Had them shipped to a buddy out of state and picked them up from him. After all that I found that they did not fit correctly onto the factory manifold. The 2 1/2” flange is too wide to fit our manifolds. The 2 bolt flange bracket did not even fit their flange correctly and wasn’t even round. There was no way they could install and not leak. At least I could return them from CA. My solution was to make my own flange from 2 1/4” pipe only about 1 1/2” long and weld them to the 2 1/2” down tubes that I also had made by following the bends of an original 2” Firebird pipe. They came out perfectly.