Will this work for warmed up cj

[ScotiaFE]

If it was my 428, I would forget about the dish pistons
and get some flat tops and zero deck it and get the compression
up into the mid 10's.
Keep the timing cranked up and the rpm above 2500 and run it hard.
But I'm a bit of a cock eyed optimist. 

[My427stang]

The Diamond with a 10.160 deck height and a 1020 Felpro would be about 9.7:1 if I read your post correctly (14 cc dish)

The Ross would be approx 9.5:1 at 10.160

Both using a 76 cc chamber

You'll notice I wont tell you how much to cut, because it depends where you are now, if I say cut 10 thou, and its already been cut, it'll be too much.  Need to have your machinist measure the decks and cc the heads first, either of those pistons could work depending on where the heads come in

[blykins]

I use a little of everything....Mahle, Probe, Racetec, and Diamond.  The good thing about the Mahle piston is that they come coated on the crown and skirt.  They also use a 1.5/1.5/3mm ring pack out of the box. 

Diamond is nice because if you need to make one change, for instance, a volume change, compression height change, etc., it's a minimal upcharge, especially for us who have MWD accounts with them. 

Racetec is another strong shooter for nice pistons.  They will do full customs for me for around $550 a set. 

The Probes need a little "dressing" out of the box, but the Diamonds, Racetecs, and Mahles are all detailed really nicely out of the box and don't require much final work before you use them. 

[blykins]

Diamond Clevor piston....



You can see how the valve reliefs have all the edges broken.

Diamond 427FE piston....



Diamond 496FE piston....







Mahle SBF piston...





Mahle 482 FE piston....







RaceTec 501FE piston...(image says Mustangs & Fords magazine, their photo, but my article, and my engine....)

[mike714]

I'm waiting on my main studs to ge here when I get them going to hone the mains then measure the deck and cc the heads I'm pretty sure they have been cut . I'm trying to keep the motor under 10:1 I had some problems with the last 10:5 motor I ran on pump gas (inconsistent fuel from pump) . On my mercury racing outboard motors you can not have ethanol fuel in them so I use to have to test the fuel all the time . Even with stations that made the effort to supply ethanol free for us ,there suppliers would mess it up by putting non ethanol 91 in tank that previously had lower grade ethanol fuel in it ,and octane levels were all over the place and I had to usually mix 110 with pump gas to get 91 to 95 ethanol free. That is why I'm being cautious with my compression. I know what comes out of the pump. I'm not even going to mention water in fuel you you get from a gas station. If you are curious about your gas station go to any marine supplier and get a test kit bass pro use to have them too you will be surprised at what you find.

[My427stang]

We can get you there, don't worry, been running my 10.7:1 489 on anything from 87-91 (usually 89 or 91) since 2006 and my 10:1 445 on the same.

Static compression is only one part of it, tight quench, mixture, cam timing, engine temps, and of course ignition timing all come into play too. Lots of guys do what you want to do on here