Porting stock exhaust manifold

[Ramtacular]

Anyone have comments or suggestions on porting and polishing stock exhaust manifolds of a '99 Ram 1500 5.2L?

[Dr. Mopar]

Originally posted by Ramtacular
Anyone have comments or suggestions on porting and polishing stock exhaust manifolds of a '99 Ram 1500 5.2L?

I have a performance engine building shop and have done flow tests on ported exhaust manifolds. spend your money wisely and buy a set of headers . Bruce , Toth Performance

[451Mopar]

I don't know about the newer '99 truck manifolds, but I have messed with the older small block manifolds and my 383 HP manifolds and only noticed a very small gain.
I then put headders on and dropped my 1/4 mile ET's 0.3 to 0.4 second!

A friend of mine with a small block Chevy did the extrude honing of his exhaust manifolds (this isn't cheap, about $500) and it din't help very much either compared to headders.

One of the Mopar Magazines, I think Mopar Muscle or Mopar Action, did the same thing. They did the extrude honed HP exhausts on a 440 and it only helped a small amount, later in another issue they installed headders and picked up a few tenths in the 1/4 mile.

I think the issue is that the tuned header length helps scavenge the chamber alot better than good flowing, but un-tuned manifolds, so it's not just a low restriction flow that is important, but the tuning effect of the headders that seems to make a big difference.