[b-man]

The Ram Air/HO manifolds might buy you 8 to 10 horsepower at the most on a stock or near stock engine.

They’re a nice upgrade (and really mostly eye candy) but once you’re done you’re into them close to a grand once you buy the manifolds, filter adapter and the down pipes that are compatible.

Simply upgrading your exhaust to 2-1/2” and keeping the original log style manifolds might make more sense economically and will provide a nice boost in performance. PYPES exhaust sells some 2-1/2” down pipes that neck down the first few inches to 2-1/4” to match up with the manifold outlets.

The 350, 400 and 455 engines all used the same standard exhaust manifolds so it follows that the 350 would see the most flow and least restriction from them cubic inch wise.

So the same 2-1/2” exhaust system using both manifold styles might have a 5 horsepower difference. The standard log manifolds really aren’t as bad as most people think. The GTO style and long branch style are very close in performance, there isn’t a big difference it’s just whatever fits your chassis.