Well I sold it and moving onto another one, a friend with a 2010 cummins borrowed it when his truck was down and just had to have it. For a replacement I bought a 2015 5.7 4 door 4x4 long bed, same basic truck but all stock with 5.7, drove it 400 miles this weekend and got 2 MPG less than the 6.4 truck did on a same trip and I was trying real hard to get good MPG. It did cost less to operate because it can run 87 octane but not a lot of difference. I was babying it to try and squeeze more MPG out of it and keep it from downshifting all the time... It had to down shift a ton more to get up hills and never had anywhere near the TQ the 6.4 had.

I have another 6.4 to build for this one and this looks like the recipe I will be following.

BGE heads shaved .025, I will do the same thing with the valves, mirror polish the entire exhaust valve head in the drill press, machine the margin on the intake valve to a very sharp edge to break up the fuel drops and minor porting on the heads along with porting the intake to more closely match the heads.

SRT8 short block

Can't decide on 5.7 or BGE cam, I feel the BGE cam will give me more power as the RPM go up but the 5.7 will give more MPG, also the switch from eagle to BGE heads will give it just a little more power as the RPM goes up and it will have a hair more compression... I thought about retarding the 5.7 cam a few degrees to give it just a tiny bit more time to push on the piston before the ex valve opens. Anyone know how much I can retard the cam timing before I get a computer code?


The other option I been considering is an eagle 5.7 with a piston swap to the early pistons, not gonna have the TQ of the 6.4 but could possibly do better MPG again with premium fuel only of course and I can easily sell the 6.4 to buy long tube headers and a vararam...