Twin Turbo 383 questions

Turbos have been spinning thousands of RPMs with bushings in industrial applications since before most of us were even thought of. Unless this is a serious all out race app the ball bearing unit is a luxury that may actually have potential for failure before bushings. There is a guy back east running a boosted 383 in an orange Challenger that pulls in the 9s! I think it may be supercharged instead of turbos but still some good info on what to do to the block to take it. Small will spool faster which is nice on a street car. There are several charts available to help match turbine size with displacement. One article in Hot Rod archives should help you a bunch.

http://www.hotrod.com/techarticles/engine/hrdp_1008_whats_new_in_turbos/new_technology_in_turbines_rear_mounting.html

"One Turbo or Two?
Single big performance turbos might be required to conform to specific sanctioning body rules limiting the number of turbos, or in narrow-bodied Bonneville Streamliners with clearance problems (which don't need to spool up quickly anyway). Fortunately, they're available: Turbonetics' large 115mm-inlet compressor can support 2,800 to 3,000 hp on gasoline; a 122mm prototype in the works can support more than 3,000 hp. Precision's HP118 turbo is rated to 2,800 hp on its own, while Pro Mod 108s can support more than 4,000 hp when used in a twin configuration. For the majority of nonconstrained applications, the crossover point from single to twins is still in the 700-to-900hp range, however."