Supercharging a 396

[ChaseN]

Hi

I have a newly rebuilt 396 I am thinking of supercharging until I can build a motor for boost. It has a 10:1 CR, all forged internals. I know the CR is higher than ideal for forced induction but according to ATI here I can run up to 12 lbs intercooled. I am planning on a more conservative, intercooled, 7-8 lbs that should, theoretically, give me a ~45% hp gain, correct?

Basically, I want to know if you think 8 lbs of intercooled boost is safe on this engine? If so, I'm pretty set on doing it.



Thanks for your time

[camcojb]

You should be able to do it with the correct tune and intercooling. How do you know you're compression is 10:1? Have you actually spec'd it out?

Jody

[ChaseN]

Well, I actually haven't spec'd out the compression ratio, but the guy who rebuilt the engine said he rebuilt to stock 396/350 specs using NOS pistons he found, which puts it at 10.25:1, and with the addition of a thicker headgasket brings it down to 10:1 he told me

Thanks

[camcojb]

The reason I ask is that most pistons are rated at pretty close to "0" deck, with a certain head chamber cc. Most all factory motors have the pistons down in the hole and the majority of the heads are larger (or at least different) than what the manufacurer claims. It's very possible to be much lower than you think you are. If he didn't calculate it out with the deck height, verify the head chamber cc, piston volume, etc. there's no real way to know.

Jody

[TurboLark]

Hi

I have a newly rebuilt 396 I am thinking of supercharging until I can build a motor for boost.

I dont understand this. A supercharger makes boost.

[camcojb]

I dont understand this. A supercharger makes boost.

I took him to mean that he'd like to supercharge the current engine until he can afford to build a blower-specific engine. In other words, have fun with the blower now on low boost and then transfer the blower to the new engine and really have fun.

Jody

[ChaseN]

I took him to mean that he'd like to supercharge the current engine until he can afford to build a blower-specific engine. In other words, have fun with the blower now on low boost and then transfer the blower to the new engine and really have fun.

Jody

Jody - thats exactly what I meant, thanks for understanding. Now, the pistons are new old stock, supposedly original to a 350 hp 396, how can I find the piston volume? I've googled it and cant find anything.

THanks,

Chase

[pdq67]

Are you sure the 350hp/396 stock pistons are forged??

pdq67