How much quench can I run?

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GotDart

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I am ready to order some Cometic MLS head gaskets so I can button up the top end of my 416 stroker. My short block was zero decked and I will be using Edelbrock heads, so quench is equal to the compressed gasket thickness. The rotating assembly is a Mopar cast 4" crank, Eagle H-beam rods, and Ross forged pistons (21cc dish) all internally balanced. Should I play it conservative and go with .040", or can I 'squeeze' a bit more out of it (pun intended) and go with the .036". My cam is fairly mild, so I don't expect to go over 6000rpm too often.

Lift w/1.5 rockers - 0.525/0.510
adv dur - 283/298
dur @50 - 236/248
lobe centerline - 108/116
lobe seperation - 112
 
I would play it consevative. I like your thinking though and I know .036 will work but still like .040. But then again being a steel rod low RPM motor to get the full quench affect the .036 would be better, marginally. OK, not much help, I know. 6 of one half dozen the other. Go with .040. No wait .036
 
Id go with the .040" how ever I think the dished pistons are going to kill the quench effect. Your compression will be just over 10:1
 
Adam, yeah I think the dish will negate some of the quench effect too. However, eventhough the pistons are dished, they do have quench pads that line up with the deck area of the Eddy heads. Here is a bad pic of the piston dome...
piston_top.JPG

Sorry it's still wrapped in plastic when I took that. But you can see the area above the valve reliefs and that small pad below the dish are at the compression height for the piston and they line up with the deck surface on the head. Hence my question, should I try to squeeze an extra .004" of quench out of it?
 
I would shoot for .040. Just use the .039 felpro gaskets. You may still loose some quench effect with your pistons. Here is a pic of my piston thats going in my 440. Its a KB piston with a quench pad for open chamber BB heads. I will be using them with my milled 906's and I went with the Cometic gasket. The quench pad sticks .055 above the deck and my chambers are .020 deep. So with the .074 gaskets I got it will have right about .040 quench and 10.0 comp. If your piston flat matches your closed chamber head it may still have good quench effect. Ron

121192735.jpg
 
From what I have read 0.040" is about ideal. When I built my 360 I used magnum heads and KB107 flat tops at zero deck with a 0.039" Felpro head gasket. This works out to 10.6:1 compression. The quench area is certainly doing it's thing because I can run 89 octane mid-grade gasoline in this engine with no detonation issues. The timing is 35 total, 12 intial and it's all in by 2300-2400 rpm.
 
Cast crank and Ross pistons and a street engine, I'd keep it at .040.
 
I ran a KB zero deck piston w/ edel. heads and a fel-pro .039 gasket without problems and great power. This is a good area to be in. The .004 isn't really worth squat in power, but just that much closer to problems.
 
Okay, I am going with the .040" Cometics. Next question, where should I order them from? I see Don at FBO has them on sale right now for $130 a pair. Is that a good price?
 
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