ihdude

iTrader: (1)

I have a 2001 Chevy 2500 ECSB with a 6.0 and a 5 speed. I'm thinking of pulling the heads and having them milled to increase compression. I assume I can have them ported if I want also. I'm also thinking of using Comp Cam XFI RPM, XR269HR. I assume I'll have to have the springs replaced. What kind of gain should I expect with this setup? I already have longtubes on it.

ihdude

iTrader: (1)

bumping it

lukesdad04

You will have to get hardened pushrods and springs. I would guess a 40 to 50 rwhp gain.

lukesdad04

And if you mill the heads you will have to measure for correct pushrod length also. Shorter than stock.