1slow01Z71

iTrader: (36)

If you are going to get aftermarket pistons you can make your compression pretty much whatever you want so get the heads if its a good deal.

tarinitup

iTrader: (11)

Deal on the heads looks like its going through and I need to know what cc pistons to order so that I can have a 10.5 ish compression with stock gaskets.

thunder550

iTrader: (70)

http://www.diamondracing.net/cocalc.htm

tarinitup

iTrader: (11)

I tried that and I have no idea what the answers are for any questions exept the bore size, number of pistons, and head cc's.

Quik

iTrader: (7)

a 243 head on a Lq4 stock will bump cr up to 10.5... a 243 head on a LQ9 will raise it to 11.1. i had 243 on my old 6.0 and it was 11.1

tarinitup

iTrader: (11)

The deal on the Heads went through and now I have some more questions. Heads are stage 2 ls6 with 59cc and the pistons I ordered are 16cc dish pistons. The guy I ordered the pistons from told me that set up would give me around 10 to 1 compression. Is that correct? I wanted 10.5ish compression but that was the best match I could find with 59cc heads. Machine shop said no bore was needed so pistons are stock 4'' bore. I guess when this comes together it will be practically the same as a forged lq9.

tarinitup

iTrader: (11)

I finally plugged in more numbers and with 4'' bore, 6.125 rods, 59cc heads and .052 gasket thickness and got 9.7 compression ratio.

I messed around with the calculator and I'm going to mill the heads .030 to 55cc and that should put me around 10.2 and a little higher if I go with thinner gaskets.

Richard@WCCH

iTrader: (3)

Be careful about milling the heads a bunch more. The head core's deck thickness is getting thinner and thinner. That leads to failed head gaskets or torched pistons. To get to 52cc from the stock 65cc LS6 head we'd have to mill .078". That's way too much in my opinion. It'll only lead to trouble down the road...............

Good luck with your newly acquired heads. If the prep work is halfway decent your engine should run pretty sweet.

Richard

tarinitup

iTrader: (11)

The guy I bought the heads from told me that patriot welded in material and then worked them. The 59cc heads are unmilled. Does that sound like right? If they are unmilled could I take off .030 to bump up compression or should I just leave the 9.7 compression and not mess with the heads. Last thing I need is repair on a new set up. Thanks

Richard@WCCH

iTrader: (3)

Now that makes better sense. I missed tdrumm's post about the welded chambers. Welded combustion chambers will reduce the volume nicely and help airflow in most cases. Milling .030" will probably net you 5cc of volume. I don't know what your piston deck height is so I'll go with zero.
Milling 5cc will pump the c/r up to 10.24:1. I see that milling 3cc will get you to 10.02:1. I use .006" per cc of milling so removing .018" will get you to 56cc.

Good luck,

Richard