How Much Compression for a Stroker?

I did a 470" low deck.4.375 x 3.900, 6.760 rod. Right at 10.2:1. 84cc Eddys and a small dish(mirrors the chamber) w/.039 felpro's at 0 deck.I know I could have went higher,but I am unsure what pump swill will be available in a couple yrs. Has a 242/248@.050 solid roller,runs great on 93 and no ping on 89(that was an oops at the gas station ) This is a street only car.Hope that helps.

http://www.projectpontiac.com/ppsite/content/view/16/30/

Try this link, it works well and gives you a look at both CR and DCR. You will need the cam specs. I would say iron heads under 8.5:1 DCR.

i still think your all nuts just entered my specs and this is what i got

499.1 ci
8.18 lifter
13.76 to 1 static
10.46 to 1 dyna

off 93 oct, 34 deg timing and 915 heads

Did he say open chamber heads ?? I did not see which heads he said other then iron heads. That said I use 906 open chamber iron heads in the 440 in my 63. And I use the KB quench pad pistons. I had to work the pistons and chambers to get all my chambers in the .040 to .045 quench area and I got it to come out at 10.0 comp. I can run 38 total timing all in by 2000 rpm and I run 92 and 93 pump with no ping. I use the MP .557 cam with 296 advertised duration and it works nice with my combo. Ron

In part it depends on how you'll use it. Pushing compression up on a drag car which has a short run followed by cooldown is different than on a street driven car that will see traffic, high underhood temps and possible sustained hard running.

I guess I'm more conservative than many posters or perhaps its because its how I use my car. Your combo sounds like you plan to drive it based on cam and convertor choice. Also if you start with open chamber iron heads and convert later to aluminum, you won't be able to use quench dome pistons very well so the iron headed engine probably won't be a quench engine.

Assuming you are starting with open chamber iron heads, I'd shoot for mid to high 9's - say 9.7 - with a D dish piston at zero deck. When you put smaller chamber aluminum heads on that would get you in the low to mid 10's. You might be close on detonation with the iron heads but should be bulletproof with the aluminum heads and quench.

Sorry guys didnt specify, they are 516 closed chambers. I know I know, they wont work well but they have a fresh valve job and I cant see dropping the dough for machine work on a set of 906s and the price of cores for something that will get changed a year later.

Closed chambered 516's now and are you going to closed chambered alum ones when you switch(hope so) & if so are the cc's of the 2 close enough that you can get your CR where you want it now & have it pretty much the same when you switch to alum heads & you'll still have your quench(if you get it now) & if the cc's are radically different & you're switching in a year I'd get the CR where you want it based on the cc's of the upcoming swap

10.5:1 should be safe. 11:1 if you run premium and the engine has good cooling (does not run hot.)