Building the following 350: 350 .030 over AL L98's ported to 64cc .051 head gasket TRW forged pistons (l2256) Lt4 hot cam or ZZ4 cam haven't decided yet 1.6rr's. TRW says with these pistons on a 64cc head you are looking at 9.72 compression ratio, however that is why I went with a .051 gasket to lower the compression even more. I want to be as close to 9.5 as I can. I am thinking of a small amount of pontential boost later in it's life. Also what rings does everyone suggests for a daily driver, and what kind of RWHP am I looking at? thanks James

You don't "port" heads to a combustion chamber volume. You have to work on the chambers. You "port" the ports.

9½:1 is too little CR with aluminum heads. You need to be a little over 10, maybe up to 10½:1.

Leave the chambers alone; port the ports; and use the Fel-Pro 1044 head gasket (.051" thickness installed). That should put you about where you need to be.

If you're running a long-tube runner TPI, it won't matter what rings or pistons or bottom end you use, the TPI will protect them from ever seeing any significant stress. I'd suggest the regular Speed-Pro moly rings, and their hypereutectic pistons. Get new rod bolts put in the rods, ARPs or something, that's about the only thing below the head gaskets you should really do anything to. Anything else would mostly be a waste of money.

9.5:1 is good for up to 8 psi (depending on cam), but I wouldn't go anymore than that with compression or boost.

Moly rings are good for superchargers.

I wouldn't recommend hypers if you're planning on boosting it. Forged are great insurance. If you were going with 4psi and 8.5:1 then the hypers would hold up pretty well, but I doubt you want to stay that low.

Granted there are tons of people running 12 psi on LT1s and IIRC, those have hypereutectic slugs, but that's because those people spent so much money on the car and the SC they don't have any money left to tear out the motor and drop forged pistons in it. If you're gonna build it for boost, BUILD IT FOR BOOST.

Maybe you already have the pistons, but if you don't get dished pistons and don't hog out the chambers of those heads. The smaller chamber with dished pistons provides more quench area which is better for boost.

What about these?

http://store.summitracing.com/partdetail.asp?part=6454

Are you suggesting this with aluminum heads in mind?

Ben

With stock aluminum castings (read 'thin deck surface'), for an everyday driver, for REALIBLE power...... Yes.

Plus (as I also said) it depends on the cam. A cam that allows high cylinder pressure will be more prone to detonate than one that doesn't.

It's kind of like how you can get away with more compression (or more like 'need' it) if you go with a lumpier cam (i.e. more overlap.)

Static compression is AKA "theory" compression. The lower your cylinder pressure, the higher static compression you can get away with. Actually that's why a lot of the cams with more overlap recommend higher compression ratios to make up for the loss of cylinder pressure.

This is kind of a catch 22 though since a cam with a lot of overlap is the LAST thing you want when using forced induction. Too much overlap shoots the intake charge right out your exhaust pipe, so the goal is to use a cam with more duration, but less overlap. If the cylinder fill is high then detonation is more likely to result.

A lot of it would depend on the efficiency of the intercooler as well. But not knowing that info, I'd rather give him a safe haven instead of a "should be OK" answer.