340 exhaust manifolds

Plus HONESTLY unless you just like to throw money OUT THE WINDOW...look into a set of 318/360 manifolds. I think most people realize now on a mild build up that the "vaunted" 340 manifolds gain a WHOPPING 1-2 HP over 360 log manifolds on a 300 HP engine...right? And even on more of a build it may jump up to 5-8 HP more mabey of its really cammed up or something...but when you think of it..is a full set of EXPENSIVE(unless you get lucky) 340 HP manifolds for $400 bucks+ worth that extra 2 HP over a set of 360 manifolds that are dirt cheap?


http://www.moparmusclemagazine.com/techarticles/155_0307_mopar_crate_engine_exhaust/



Exerpt from the Mopar Muscle test on a 300 HP crate 360

Log 318 manifolds

For our baseline test, we fitted the 360 with the lowest of exhaust low, a set of stock small-passage 318 iron exhaust manifolds. Bolted to the manifolds was a set of 21/4-inch head pipe extensions 24 inches long. So equipped, the 360 put out a respectable 311 hp at 4,600 rpm and 403 lb-ft of torque


log 360 manifolds

We moved up a notch from the early 318 iron manifolds to late 360 iron log-style manifolds. The 360 manifolds are nothing to look at, but the internal passages and outlet are significantly larger than those of the 318 pieces. Power was up a little, moving to 314 hp and 407.1 lb-ft of torque.

so far from 318 to 360 they are up a whopping 3HP and 4ft bls torque

and now Drum Roll!!!!!!!!! the VAUNTED(term used VERY lightly) 340 HP manifolds

Our final test of factory iron was a set of rare and expensive early 340 high-performance manifolds. With the 340 exhaust, the 360 inched up to 315 hp and 409.1 lb-ft of torque, which represented very little gain on this engine.

so the results...from a 318 LOG manifold you gain a WHOPPING 4HP if you go with a 340 manifold and a WHOPPING 1 HP and 2 torque over log 360 manifolds.

guess what I was trying to point out is 340 HP manifolds are expensive BUT GIVE VERY LITTLE GAIN over 318/360 manifolds on a typical 300(311 hp by the results)hp engine. so I was just trying to possibly save you $$$ vs VERY LITTLE performance gain.