Inliners International Forums General Discussion Engines exhaust question

hello,

i am building 292cid mostly stock for a daily driver to replace the 235cid that has died. the exhaust manifold that came with the donnor motor is in pretty ruff shape, the exhaust diverter to the intake is completely missing and a couple of broken studs that need to be drilled and replaced. question, in the wrecking yard there is a truck with a 250cid it has stock intake and exhaust manifolds on it. the exhaust manifold looks like a one piece dual exhaust manifold (two exhaust pipes leave it and join into one pipe by the z-bar for the clutch). has anyone seen one of these before? could i use it without losing any performance over the stock manifold i already have? could i run dual exhaust from it and get that castiron header sound? i would be grateful for any thoughts, insights, experiences, or knowledge that anyone could offer. thank you!

What year is this 250?
It sounds like an intergral head with the intake and exhaust cast as part of the head. They did make some of these with dual exhaust outlets. I haven't messed with one, but if the manifold plenum is common to all 6 cylinders with just 2 outlets instead of one, it won't sound the same as a split manifold where the front 3 cylinders are totally separate from the rear 3.

Generally, it's recommended to stay away from the integral heads due to potential cracks and the lack of ability to upgrade induction.

JC Whitney used to sell tube headers for these, maybe they still do. Would probably be cheaper than Clifford. Otherwise, Tom Langdon sells a real nice set of cast iron duals.

As for the diverter, I'm not sure I would get too worried about it in SoCal. Block it off, and it should be fine. At least until you find what you really want. Studs can be replaced.

If the manifolds are really separate from the head, I wonder if they came off a Pontiac OHC six? I think that motor had two exhaust exits. I think the ports are the same, but the bolt pattern to hold the manifolds to the head were a bit different, so drilling or grinding had to be done. If it looks like the port castings have been messed with, that could be a clue.