whats your input on a thicker head gasket ?

[BenningJ]

Originally Posted by litle88

His link to the pistons state that they are -4cc's so you decrease to compression. It's a flat top with valve reliefs. I was confused too when he posted they were +4 so that would of made them domed and waaaay too much compression.

Correct me if I am wrong but I'm pretty sure a positive "cc" piston increases the combustion chamber volume consequently reducing the compression ratio and a negative "cc" piston reduces the combustion chamber volume increasing the compression ratio.

For instance, I am looking at getting pistons for a 383 build (Gen 1 Block) and a dome piston for that style says it has a -9.50cc piston head volume where a dish piston says its piston head volume is up to +31cc.

[Alvin@PCMofNC]

Those are -4 cc for the valve reliefs. I'd shoot for 10.2-10.8 for a street supercharged/turbocharged motor on 93 with less than 15 pounds. Go with a LS9 gasket. Keep a wideband on the car to watch the tune and you shouldn't have any problems.

[1sick7]

Originally Posted by Alvin@PCMofNC

Those are -4 cc for the valve reliefs. I'd shoot for 10.2-10.8 for a street supercharged/turbocharged motor on 93 with less than 15 pounds. Go with a LS9 gasket. Keep a wideband on the car to watch the tune and you shouldn't have any problems.

Do you know the compressed thickness ? Some say .55 and other web sites say 0.51?

[willhe64]

Originally Posted by Alvin@PCMofNC

Keep a wideband on the car to watch the tune and you shouldn't have any problems.

Air fuel mixture has little to do with detonation although a lean condition will almost always detonate because we run them close. Bad fuel will detonate in a rich mixture. Too much timing will detonate in a rich mixture. That's why there is a knock sensor.

[Bo White]

I would never run a thick gasket unless I have to run a block that has been decked to the point that the piston is .015" or more out of the hole at tdc. Run the thinnest gasket you can get away with and adjust the compression ratio with the piston design and/or the chamber size.
I've ran gaskets thicknesses to were I had .028" piston to head clearance before but I don't recommend that on a street engine. The further the piston is from the cylinder head the less effecient the engine will be given the same compression ratio. Let the combustion chamber do its job. You want as much of the air/fuel pushed into the combustion chamber as possible. The more residual air/fuel that dwells in between the piston and the deck of the cylinder head the less effecient the burn will be. Since the pistons have already been bought just increase the chamber size of the cylinder heads and run a gasket that gives you .035-.040" piston to head clearance and it will run better and make more power with the same given target compression ratio.