dhdenney

iTrader: (53)

Was just wondering if anyone has milled their Lt1 heads. If so, how much did you mill and what kind of CR did you achieve/gain? I was thinking of milling mine in the future after I get a bigger cam, which would allow me to do so.

DietCoke

iTrader: (18)

If you mill the combustion chambers, compression goes up quick. Be careful not to hit a piston with a valve, milled heads+ big cam/overlap can do that

dhdenney

iTrader: (53)

I've got 16cc dishes so I wasn't really too worried about it.

solid95z

iTrader: (7)

My heads are 51cc with a ZERO deck block and a CC 306 cam and I have no p/v clearence problems. The total compression is 12.344:1 and it runs great on pump gas.

Stock LT1 heads are 58cc

dhdenney

iTrader: (53)

Awesome, that's the kinda info I was looking for.

JodyJ

iTrader: (3)

When you milled your heads, did you have to mill the intake also?

Thanks,

Jody J.

00Z-28-LT1

iTrader: (1)

man....i have a long block that i bought and was installing in my car but the intake will not fit cuz the heads were decked.......what do i do???

solid95z

iTrader: (7)

YOu need to find out how much they were milled and take the intake to the machine shop and have them angle mill the intake to fit properly.

Scott

solid95z

iTrader: (7)

I have installed heads that were milled to 52cc and the block was a stock deck I did not have to angle mill the intake. But mine are 51cc and the block is a 0 deck and I did have to angle mill the intake.

dhdenney

iTrader: (53)

Wonder if it would be safe to assume all stock deck blocks wouldn't have to have the intake angle milled?

solid95z

iTrader: (7)

I've done several head/cam installs with milled heads that I did not have the intakes angle milled and they were fine.

96-speed

iTrader: (19)

Scott, did you personally measure your stock heads to be 58cc?

Ryan

solid95z

iTrader: (7)

In '98 when I first got into LT1's real heavy, I was working at L&B Performance and we had a few sets cc'd just to verify what the dealership told us and our machine shop did confirm that they were 58cc.

00Z-28-LT1

iTrader: (1)

how do u put the intake in a mill, i have a bridgeport mill but took the intake to a machine shop anyway. i figured i needed some kind of mounting plate...........?

regorih383

iTrader: (21)

how the hell can you say the you are running 12.3 somthing compresion on pump gas and that its ok ..... thats crazy on 93 octang that would of knocked so much it would of blown up!!! talk abouy risking it all the time>>>>>

solid95z

iTrader: (7)

Well....YOU do the math:
0 deck block
51cc heads
.039 gaskets
3.48 stroke
-5cc pistons

How do you run 12.3x:1 compression on pump gas, it's called TUNING!!!!! I have built motors that run more than that on pump gas. I took part in building a 434 C5 at Speed Demon Motorsports that had about 13.4x:1 and it runs on pump gas. It doesn't like it as much, dut it doesn't have any problems. My best friend Tony Shepherd, his hydraulic 396 is 12.6:1 and his runs fine on pump gas! Actually that car made 479 rwhp on pump gas.

dhdenney

iTrader: (53)

I'm not as good on the math as Solid95z but when you run longer duration cams, the intake valves close later than a smaller duration cam would. The dynamic compression is thus reduced (more critical than static). The bigger the cam, shoot for the sky on compression. That is why I am having a custom cam ground with some advance in it--to get my dynamic CR up into a better range since it will be SO low with long duration in a relatively low 10.8:1 motor.

solid95z

iTrader: (7)

Exactly right!!! Typically the more duration you have the more compression you can run becuase the valve is closing later and will bleed off the extra compression. The CC306, which I have, bleeds off compression very well, which allows me to run a higher compression.

dhdenney

iTrader: (53)

How much advance would you guess I would need with about a 239/248 cam? I imagine the guys at Comp will have a handle on that but just for the sake of discussion....... If I can hit money on this cam, then I can skip the head milling!

5w20

iTrader: (21)

Do you know the specs of the cc306 cam with 1.6RR? So that cam would be a good choice to run about 12.5 compression correct, since you have 12.3XX compression. I heard that this cam is great for nitrous, is this true? What kind of CC's would the heads have if they were milled .020"?