Questions about supercharged engines ?

My son wants to supercharge his 400 in his Dart. Myself I have never fooled with supercharged engines. So I was wandering as I figured about 9.0 comp is what we want to shoot for ? And do supercharged engines even worry about quench since I guess its tuffer to get with the lower comp ? He wants to use a blow through carb also. We will also have a custom cam made for it. Thanks for any help. Ron

9:1 is frequently used, good compromise between NA power/torque/mileage and boost tolerance. Less static CR allows more boost at the expense of NA operation, my turbo is 8.5:1 and 30 psi boost. Quench is still desirable.
Read my article http://victorylibrary.com/mopar/blower/blower.htm

Thank you , Ron

Which type and size is he wanting to use?

Ron, my hemi pistons were cut for 9 to 1 and will be using my 14/71 Littlefield roots.

IMO quench matters, especially on pump gas since you will find it difficult to reach MBT before detonation, especially on these motors that like alot of timing. The engine will not tolerate as much timing under boost, BUT it also doesn't NEED as much timing either. With boost detonation can get really destructive really quickly. If you're running quite a bit of boost, and you can hear the detonation, you probably already broke it.

If you're limiting this to mechanical blowers (no turbo) a Procharger is an easier fit (clears the hood), boost change = pulley change, can be intercooled if blow-through carburetor (Roots/Eaton not easy to do).
How much power is he looking for? 5-10 psi is a nearly stock engine with careful controls, 20+ psi requires more $$ in the hard parts.
Carb or injected?

Is this race only on race gas or is it still a street and strip deal? If race only pump the compression ratio up to 10.0+ to 1 and use methanol as the fuel, maybe use E85 instead

Depending on your targets, the meth injection kits, like Snow, have some real advantages for boosted engines.

I had a 10/71 on a 505" Hemi. And it was monster.

After you drive his, plan on getting one for yourself.
My personal preference is Vortec. the transmissions are quieter, and you can call them and buy any part for them if needed. Prochargers sound "angry" with noise even at idle. They wont sell you as much as a screw for one. Any problems with the unit will leave you without a blower for as long as it takes them to fix it. Sponsored cars get front of the line service, as regular paying customers wait... and wait.
I've found that serp belts are fine for about 10psi. Beyond that, go with a cogged belt. Beyond 20psi, get a support strut for crank and blower nose if you want reliable belt life. Or go with a front drive tran$.

9:1 is fine on gasoline.