Xtnct00WS6

iTrader: (8)

..that is the question.

My 243 castings are at 61.88cc's (.018mill) right now and I put some .080 flycuts in my pistons which I'm told is about 1cc. That brings my SCR to about 11.06:1 and my DCR to 8.49:1. I have a .045 gasket and a 230/234 111lsa +2 cam. I measured PTVC and I have around 270 thousands so I have some room to spare with the 61.88cc's and .080 flycut.

I'm thinking of milling the heads about .007 to bring me to 11.2:1 SCR and 8.6 DCR. What are your thoughts on my gameplan? Please critique my setup! Thanks!

Xtnct00WS6

iTrader: (8)

11.2:1 isn't too much?

92 Z28 LS-1

iTrader: (1)

11.2 isn't too much. My friend has a gmmg phase IIX 475HP package on his 02 ws6 and he has 11.75:1. just double check your push rod length, but I would play it safe and keep the ptvc high unless it was a race only car. I run a 12.5:1 on my circle track car but I use 114 octane.

onebadZ28

what octane should someone use if they were running 11.1:1?

92 Z28 LS-1

iTrader: (1)

I think 93 should be fine. 10.5:1 needs at least 91. 11:1 should be fine with 93. It will run on 87 but it is safe to use a higher octane because it is less likely to detonate and it will burn cleaner. High octane fuel is more stable than low octane fuel so you can use high compression without detonation. 87 octane on a motor with 13:1 compression will run but it will ignite too early and burn the valves and pistons.

hammertime

iTrader: (1)

Sounds good, but unless you already have it apart, it's probably not worth tearing it apart for milling. You might gain 3-5 hp for your efforts. If it's already apart, it wouldn't hurt.

Sounds like you already have the gaskets, otherwise .040 gaskets would do the same thing while reducing your quench volume and make it less prone to detonate.

Xtnct00WS6

iTrader: (8)

Thanks! It's all apart and I already have .045 gaskets that I'm gonna reuse. Hammertime, you think that a 1cc mill is worth 5 hp at the most? I guess that sounds about right.

GuitsBoy

iTrader: (4)

No reason not to, although shoudl you take the heads off again later, you wont be able to do a cleanup pass and keep the same compression without going to a thicker gasket.

Xtnct00WS6

iTrader: (8)

I didn't think about that. Thanks. Do you suggest doing a smaller mill then? Even if I do the .007 mill, do you think a .003ish cleanup mill would put me over the edge?

GuitsBoy

iTrader: (4)

No, im sure you'd still be okay. I realy dont think youll see much difference. I was just playing the devils advocate. But think about the cost of the mill. If youre really paying for it, the mill probably wont gain you all that much. If its free or cheap for you to mill now, might as well i guess.

Also, with pistons already .007 or more out of the hole, I would be cautious about moving to a smaller gasket. I know you said you were reusing yours, i just wanted to go on record with that. I feel safer with a .035 quench than a .030 or smaller. Many stock pistons have measured .010 OOH.