Here's the deal. I'm wondering what compression ratio to run with a YS-Trim on a 396? I was told it used to run 8.25:1 with a 72cc chamber, copper gskts, and a P1SC, but I have to put new heads on it and buy some copper gaskets. The Ross pistons look like a 10-11cc dish, so what kind of options do I have for gasket thicknesses to get the CR down for 24psi?

 

With 24 lbs of boost I would recommend staying around 8.25:1. I would find out what dish your pistons are and have the combustion chamber of your heads opened up to accomodate your desired compression ratio. I think overall you will make more power with smaller CR and more boost.

 

It is a drag car, and the heads didn't come with the motor. I also think 8.25 is about right. But how thick are the copper gaskets everyone is using? I'm just getting an idea right now until I have time to cc the pistons and measure deck height. In reference to piston dish was what I meant to reduce CR, as they are not dished as much as a milder engine usually is. But the copper/o-ring combo will lower CR alot, but my question would be how much? Thanks guys.

 

>Go with the Cometic head gaskets (you can get them in about any thickness) .
I know www.CMotorsports.com sells them and they will probably give you some great advice .
by-the-way I will also use the 396 LT1 with 8.5 cr and AFR 64cc heads for my T-trim and hopefully run about 12-15 psi of boost .

 

What about Nu-Teck???? Why does it say beware Bowtie??

 

What fuel are you going to run? And what cam will you use? these need to be considered before deciding on CR. And why are you stuck on using Ross pistons if they don't make what you need? Don't use a head gasket thicker than ~0.040" because that's optimum for effective quench (with a zero deck). There is a fairly decent explanation this here http://www.beckracing.com/page05.htm.

You may need a lower CR, or maybe you can use more. Giving you decent advice depends on a little more info.

Rich Krause

 

>I had a bad experiance with them ... you figure that when you pay for something you would get it right ?!?

 

what happened bowtie??? I was planning on getting a motor from them, but i don't want to if they aren't any good or helpful. Are there motors good??

 

Hey Rich,

I'm waiting for the cam specs as we speak, but I already have the shortblock. That's why I'm stuck with the Ross pistons I mentioned. That's all the info I have right now, but I just needed some more info as I was told it had 8.25 CR with those pistons and 76cc heads, meaning fairly thick gaskets, right?

As for Nu-tek, email Bowtie to find out more.

 

F-bud: most people (myself included) have good luck with the Fel-Pro 0.039" gasket.

Rich Krause

 

What gas do you plan to run?

I have a 9:1 LS6, YS trim, air/air front mount, 83 lb injectors, FAST (in transit) and will be running straight C16.

 

Also plan on running C16, John. Should have more info tomorrow to work out a few volume details. Thanks for the info.

You might even know the car. It was Rich Macdonald's red 96 Z.

 

I am currently running 9.3-1 compression with my Y/S-trim combo.
I too run c-16 and on the dyno saw 21psi. The car made just over 740 rwhp through a th400 and 12 blot. An air to water I/C was used to cool the charge.

 

Sure I know the car, I have seen it a number of times, did you guys the hood too? What did you buy?

My research basically said that 9:1 with C16 works well with a YS Trim. You can go with less CR but that's contingent on the availability of stuff that will yield 8.25:1.

 

John,

Yep, we got the whole package less heads/intake/fast.

Even got the intercooler for the hood. Just hoping the air-air works good enough.

Did you ever see it run with the P-1SC?

BlownBird,
Thanks alot for the info. You LS or LT?