Mark Johnson

iTrader: (1)

Thoughts on a 2014 truck fallen to the wayside. Thinking(for my 2006 1500) after I'm all moved over to new place of going the 6.0 route(LQ4) with a small cam and some AI241 heads to bump compression a smidge. Shooting for a compression of 9.6:1, can this be achieved with a thicker head gasket, as when I compute with the 67.5cc chamber yeilds like 9.76:1. Can I live on regular pump gas with a cranking pressure of 163psi? LQ9 is 169psi but don't know how finicky it is about octane. How hard is it to install cam and time it right? Alot of questions, but I know this is the best place for info........
TIA

1FastBrick

iTrader: (17)

Your math is wrong on the LQ4 with 241 heads. The factory compression is around 9.5:1 with 317 that have roughly a 72cc chamber... you would be near 10.:1

MikeGyver

iTrader: (5)

Where did you come up with 163 psi if you don't have a cam picked out yet? The cam affects cranking pressure and octane requirement.

Mark Johnson

iTrader: (1)

I spec'd up a cam, but back to the compression ration- I always thought that and LQ4 would be up at 10:1 with the 243/799 65cc heads so I thought I could get away with something here. But also seeing that with rise in compression the effective stroke is lessened now what's the significance of that effective stroke? Oh yeah- so how many compression points are achieved per cc of chamber reduction...

1FastBrick

iTrader: (17)

The heads are more like 66-67 cc there listed as 66.67 on the net.

I think you would be closer to 9:8.1 with 67 cc

You probably forgot to put the piston out of the hole when attempting to calculate.


LQ4 with 241 heads

1FastBrick

iTrader: (17)

1FastBrick

iTrader: (17)

not sure why picture is not showing up

Mark Johnson

iTrader: (1)

Lemme ask ya this; how finicky is the LQ9 about high or low octane gas?

1FastBrick

iTrader: (17)

Depends on quality of gas. I ran mine on 87 and didn't here any pinging but it was bone stock other than some transmission tuning changes I made.

GMCtrk

iTrader: (27)

Does GM not sell gen3 crate motors anymore? Couldn't find any on their site.