N4cer

iTrader: (11)

Anybody know the basic formula for milling the L92 heads to figure out how much to remove equals 1cc of chamber volume?

Also, anybody know where people are having PTV issues with the cams that are appropriate for these setups on say flat top pistons? I'm not changing cams yet, but will run a bigger cam later and would like to know how far I'll be able to mill and be safe, so that I can pick the right pistons.

WKMCD

iTrader: (2)

Roughly .006 per CC. No comment on the cam because you should always check anyways.

N4cer

iTrader: (11)

So its rate is the same as the regular LS-based heads? That's some odd physics if they did that.

And I'm not a n00b. I never said I won't measure, dude. Not sure where you read that I'm not measuring. That's weird. I thought only my wife could take a sentence and get a totally different sentence from it.
I'm asking so that I can plan accordingly AND THEN I'LL MEASURE. I can't measure before I even build the engine. I need to be sure to buy the right pistons.

Stang's Bane

iTrader: (22)

If you call and request L92 specific pistons, you can make sure that you will always have enough PTV clearance.

As far as him telling you to measure. You gave him an equation with two variables. He never told yoy to measure before you get the engine built. He was implying that you needed to measure when you got it built because he doesn't know
1) How much you plan on milling.
2)What pistons you will be using
3)What cam you will be using

As you know all these will play into how much PTV you will have. I would have told you the same thing.

N4cer

iTrader: (11)

Nice message board arrogance, but come on. There's no need. We know basically what setups can and can't fit before assembly, and for you to pretend we don't is just absurd. For instance: hey can I safely run a g5x3 on a 112 with stock pistons and stock heads? No. We know that. But with a 2cc relief which usually is 0.130+ deep, you can. So let me dumb it down for the wannabe smart kids:

1 - What is the formula on milling/volume? I've seen 1cc=0.010", but nobody said for sure.

2 - how much taller is the L92 head regarding stock valve drop?

3 - how much taller is the L92 head regarding pushrod length (yes in a stock block)?

Brian Tooley Racing

iTrader: (13)

1 I would go with the .006" per cc
2 The intake valve is .015" closer to the deck (.135" versus .150")
3 The stock L92 valves will not clear a 5.7 stock shortblock

So in short, you would have to mill the heads .036-.042 to get them where a LS6 or 5.3 head is, you would have less P to V then with either of those 2 heads, and you still don't have valves that clear the bore of the 3.90 block.

WKMCD

iTrader: (2)

Good luck with your build.

See5

iTrader: (53)

I took .040 off and ended up @ 64cc. This was measured by the porter.

N4cer

iTrader: (11)

Thanks Brian. Don't worry. It's going on a 408.

N4cer

iTrader: (11)

Did that leave plenty of mounting surface thickness to the deck?
That math shows that:

.040 = 5.8cc
58/4= 14.5
So every 0.010" you mill removes 1.45cc.

See5

iTrader: (53)

.040 is about as far as you want to go for two reasons:

*If you want to do a clean up later .050 is getting thin
*.040 is about it for the intake lining up with the ports.

You can always use thinner gaskets as well. I used .040 there which gave me a tad over 11:1.

Brian Tooley Racing

iTrader: (13)

Oh, OK, this part threw me off....

Quote:

Originally Posted by N4cer

(yes in a stock block)?