I would forget the 383 and build a simple pump gas friendly Supercharged .030 over 350ci motor.
Use the stock cast crank, New GMPP "PM" connecting rods. and TRW speed pro L2441F-30 22cc Dcup pistons combined with large 72cc chambered heads such as RHS 200cc iron lightnings opened up to 76cc. "O deck" the block.
i would use a Weiand 177cc Prostreet supercharger and a 850cfm carb.
For a mild/moderate temperment and great power use Crane #113801 HMV278 Cam.
If you want a more radical racy idle and more power and RPM use Crane #114681
F-280-2 mechanical flat tappet cam.
You'll make way more than 400RWHP and go like hell ...
The pump gas friendly 7.7:1 cr will allow 10+lbs of boost on 93 octane with little or no spark retard and full reliability.
Much better than a 383. Even a roller 383. Even with $2000+ cylinder heads.
Your 3.9 gear ratio is good. Use a 3500stall 9.5"/10" converter.
Not hard at all to do. If you can get the weight with driver down to 3200lbs a very very low 7second ET in the 1/8 mile is do-able.
You don't have to be a rocket scientist to build, maintain or tune it. You can drive it to work and back if you want.