willy wagon

does replacing the exhaust manifold for newer one off newer truck help to increase air flow? if so what years fit and are the best to put on. truck is 92 with big intake and 4 inch exhaust.

1972RedNeck

Nope, all 12 valves use similar manifolds. 24 valves have round ports instead of rectangle ports. The best flowing manifold would be something like an AFE Blade Runner or a Steed Speed ($$$).

j.fonder

I'd say unless you're looking to make big power, 400+ hp, it's a waste of time and money. If your stock one is cracked or warped and you need to replace it anyhow, then yes, id recommend something like an aftermarket 3 piece manifold.

Cactus92

I'm going to have to back up what fonder says. I'm pushing 275-350 hp right now and the factory manifold is doing great. As long as a person let's ro motor cool off gaffer pulling that stock manifold should last years upon years. I'm looking at the BD 3 piece manifold.