towerhand

I have my heads currently at the machine shop and wanting to know if i should mill them or leave them alone. I have a 408 with PRC LS3 heads and Diamond flat top pistons. Currently with my setup i am using .061 cometic gaskets with .013 pistons out of the hole which gives me .048 quench. The heads are 70cc and i have .200 PTV. Should i mill to acheive less PTV and more compression. The pistons will have 11.8:1, with 66cc heads, so i am currently around 11.2:1. Any help will be greatly appreciated.

Tainted

iTrader: (9)

Id always mill according to ptv clearance, while leaving wiggle room.

I wouldnt mill much, maybe .015

TurboMonte100

iTrader: (1)

Is the .200 PTV, intake exhaust or both? The exhaust is always the one to watch, as it is the one that will hit if it is late (floats). I have run intakes pretty close without problems.

Tainted

iTrader: (9)

I *believe* your clearances should be 100/120

towerhand

It was .200 on exhaust. Tell me if my comp. ratio assessment is correct? My pistons Diamond 11519 are figured at -.10(positive) I have .014 out the hole with .061 head gaskets. Compresssion ratio on these pistons with a 66cc head are 11.6:1, and 62cc is 12.4:1. My heads are 70cc, so what will my ratio be. My quench is .048

TurboMonte100

iTrader: (1)

I'm figuring 11.47. without knowing the gasket bore diameter.

Tainted

iTrader: (9)

Here you go, fully functional compression calc with all the goodies

https://ls1tech.com/forums/generatio...alculator.html

towerhand

Really great app man, my compression ratio is 11.14:1, so we will mill the heads to 66cc, which will give me 11.6:1. Thanks for your help!

WKMCD

iTrader: (2)

My best results were with CR in the 11.3-11.4 range. Above that and we couldn't put in enough timing. I ran 12.0 and picked up about 30HP by dropping it to 11:4 and could add 4-5 degrees more lead. These heads lve timing and I learned not the trade compression to timing.

Just my $.02

towerhand

What size cam, if you dont mind me asking