CR & Quench Question

[ajmorell]

I apologize in advance, but I have just been unable to find this information. I basically want a simple yes or no as to whether I'm thinking about this right.

Below is what I'm potentially planning on:

0.020" over
4.2 Crank/Rods
0.010" decking of block
stock overbore pistons
stock head gasket

According to my calc's (or the spreadsheet I have anyways) this results in:

9.51:1 CR
0.0905 Quench
4.6L/276 cu in.


What I'm leary about is the quench. I don't fully understand what's "good" or "bad" and if what I'm planning on is going to cause problems. Ideally I would like to run this on 87 but don't have a problem running 89 or 91 if I have to.

I know that I could get pistons with increased dish vol. to drop the CR and go with the performance head gasket to get the quench closer to stock, but my question is do I need to or will what I have planned work okay?

[ajmorell]

I just got off of the phone with a Keith Black tech, tell me if this sounds any better than my original configuration.

258 crank
4.0 rods
0.030" over
0.010" decking of block
stock head gasket
KB 2229030 pistons

This results in a CR of 9.2:1 and quench of +.002 over stock. I'm thinking this is the better route, the only bitch is I've already bought the 4.2 rods

[bratcop]

If you are up at MIchigan Tech in Houghton/Hancock, I would assume you are close to my elevation here in SheVegas, WI. Anyway, I would try to get that quench closer than stock. My machinist said that any benefit from quench (better mix, cooler burn, etc) is decreased as your quench increases and is nil when your quench exceeds about .070. That might be a bit of an exaggeration on his part, but I surely wouldn't want my quench near .090 or even near stock if I was hoping to run on 87 octane. I am around the .04 range with a zero decked block, dished pistons to keep comp ratio down,and the performace gasket. I run on 87 octane all day without knock. I wouldn't want to flirt with knock and would gladly spend the extra coin to zero deck the block and dish the pistons to get the smallest quench reasonably possible. Especially since you are going to deck the block anyway.

Bratcop

[gradon]

Keep the 4.2 rods because the 2229s won't work on the 4.0 rods in a stroker--that tech steered you wrong.