ZeroTraction

iTrader: (4)

Ok I picked up a bone stock 2000 ls1 from a Corvette 80k miles. Im building my first LS motor. Carbureted single plane setup with the ws6stores high lift ASA cam 226-236 .600 110, I have a pair of 243 2.5 cnc heads that I want to mill to get the most compression I can. Ws6store says I can run .030" milled 243s safely with factory head gaskets. With that said is it more efficient to run higher compression with the factory .051" head gasket stock pistons .007" for a .044 Quench or less compression with a tighter Quench in the high .030s. or am I over thinking it and splitting hairs?

bbond105

Why not have both. Use a .040 gasket and mill the head 0.20?

StealthFormula

iTrader: (35)

I think you are over thinking it haha. Run a .40 Cometic to get the quench to an ideal state (which also increases the compression over the stock gasket) and then measure PTV to see how much the heads can be milled.

pantera_efi

iTrader: (1)

Hi ZT, Higher Compression AND TIGHTER Squish is BEST.
I would fit a FelPro HG @ .041", the LS-1 small bore gasket.

This should give you a Piston/Head of .033" Quench.

Your Altitude ?

Lance

.boB

iTrader: (1)

In this case, quench is more important than compression.

You'll gain a little bit more power with the increased compression. But you'll lose a lot of efficiency with increased quench, and run a high risk of detonation when it gets hot.

A.R. Shale Targa

iTrader: (2)

Couple things to consider here. First. Milling a head usually reduces its flow
Also your proposed.044" quench with the factory gasket is a room temperature calculation. An all aluminum block "grows" considerably at operating temp and most of that .007" positive deck disappears. This also explains the sloppy timing chain issue that everyone freaks about but actually tightens up at operating temps as the cam moves "north" from thermal expansion
The cheapest route is to use the GM gaskets and mill the heads. The BEST route is to run the .040" gaskets and just a simple .006"-.010" cleanup on the deck of those 243s. You'll have a tight non detonation sensitive 11.0:1 that will clear PTV and work nice with that cam. Great all around selection of parts IMO

ZeroTraction

iTrader: (4)

Thank you for the reply guys! I will be pulling the factory 853 heads soon and I'll be able to check piston to deck height to know for sure what it is. What is a safe PTV clearance for these LS motors? When checking PTV do I need a solid lifter vs a hydraulic type like a gen 1 sbc?
I don't mind spending more money on the good head gaskets...what brands/typs do I want to be looking for? Thanks again guys for the help

ZeroTraction

iTrader: (4)

My Altitude is 2,750 and 91 octane is the highest I see these days in Idaho. This setup is for a 70 Camaro with a manual transmission and 3:73 gears. It's setup for autocross and a weekend hotrod. I'd love to have as much low/mid range I can get with this combo hence higher compression!

AnotherWs6

iTrader: (17)

The more you mill the greater the chance for your heads not to line up right. I wouldn't go much more than 20 on the heads.

A.R. Shale Targa

iTrader: (2)

In "MOST" cases you can get the intake to fit when the total from milling and/or thinner gaskets does not change more than .040"............

tech@WS6store

iTrader: (2)

The pistons expand as well as temp increases. The type of material will determine how much. Also rpm will stretch a rod.
There are many ways to look at it, but like i said before, with a mild combo youd see better gains from the incressed cr vs quench in this area.
If you want to spend the extra time and money and can accurately measure, then doing both will help, but youd want to buy 3 gaskets so you can torque one down to check.
The alternate version is just do both and flycut.
Ive done that before, but only on more "max effort" higher duration cams.

tech@WS6store

iTrader: (2)

Right. over .030 seems to be a point of diminishing returns to me.
Quite a few like to use 317s on the cheap then mill the hell out of em for cr...which, as discussed earlier, effects the flow substantially esp on a smaller bore.

Damacman

Also ended up with this cam without a cam card! Can anyone help identify it?

tech@WS6store

iTrader: (2)

Looks like a cammotion 232/251 with 353 lobe lift 112lsa +4

speedtigger

iTrader: (16)

That looks like a Crane Cam to me. Not one of ours.

tech@WS6store

iTrader: (2)

Noted. The writing is very similar and and abbreviations et

fastlt1

iTrader: (4)

99 z28 ls1. Sbe with 243s shaved .030 and gm mls. What would quench be?

tech@WS6store

iTrader: (2)

Shaving ls heads doesnt change quench.
You cannot calculate it without knowing piston to deck clearance also. Otherwise youre fishin in the dark.

fastlt1

iTrader: (4)

oh. So on sbe only headgasket thickness effects quench

tech@WS6store

iTrader: (2)

On any ls bottom end, stock or otherwise. 3 things effect quench. Piston to deck clearance and head gasket thickness, and head gasket bore. since quench is an area you have to factor that in as well. Running too big a head gasket is bad for quench and cr.