340 vs 360 confirmation

Woodsman341 said

I'm not saying you're off track a little, because I'm certainly not an exhaust expert, but it seems optimistic that I'll gain 50 horsepower as you said, when all the other reading I've done in the last week or so indicates somewhere on the neighborhood of 13-20 horsepower gain, tops. Unless I misunderstood you?

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Gains depend on cam profile, head flow, head flow numbers, stroked or not, and dozens of other factors. A stockish type low cam lift stock port engine will have modest gains like you are thinking. A stroked small block ported aluminum heads 600 lift cam ect will be gaining 50-60 or more hp with headers straight through mufflers bigger pipes etc. So its a depends no blanket one size fits all headers will gain this much all the times ect etc etc etc....

A lot of times ppl have say 340 manifolds with stock head pipe thats 2 inch off manifold pinch 1/2 inch around torsion bar then goes into 2 1/4 pipe drivers side. They take all that off swap on headers mandrel bent 2 1/2 pips see a good gain say see headers for the win. Put some 2 1/2 TTI mandrel head pipes on 340 manifolds base line that first then go to headers that a more accurate comparison. But of course most ppl gonna just go gloss over those so called details right???

Then you got stock chrome tips with inner diameter like 1 5/8 choke point where they slide in the pipe. Choke point.

So you can run manifolds on mildish builds with mandrel bent 2 1/2 pipes, straight threw muffles, tips that slide over pipes not into them, and its gonna flow way more then the original exhaust.