Performance Gain With Headers?

[74 Rayson]

I have a stock 454 with the manifold and snail set up. I am wondering what kind of performance change, if any, I will get by putting on thru-transom headers?

[asch]

From what I understand, it's worth it. But it helps to have the rest of the motor configured properly. I'm considering doing the same.

[HOSS]

My experience has been notably improved midrange.

[twowheeledfish]

I just did this with my 460. Except now I'm running a bit lean. Surging and power drop off at top end, even after going up 8 jet sizes. Meter plate drilling to follow....
I'll get it sorted.

[jbone]

gained 200 rpm with Lightning jacketed thru transoms on a zz502. I think thats about a 50 hp bump. You could gain more, because I had decent flowing Indmar exhaust manifolds, no snails.
Most people I talk to also gained 200-250 rpm.
Hope this helps.

[ck7684]

Most people like them and gain about 50 HP and a couple hundred RPM. I'm running logs, but I dont need any more power or speed :D