You won't find a better carb than a Q-Jet. Personally I would use a 78-84 model without the dual capacity accelerator pump or mixture control solenoid. 17083226 or 17084226 or the like. Those have the larger primaries and flow up to 850 cfm. Get one built and recalibrated by Cliff Ruggles or Sean Murphy Inductions and it will last for a long time.
Option 2 would be a Sniper TBI system. Throw on a used 7101 performer rpm manifold at the same time so that you get the correct square Holley flange without using a flow reducing adapter.
Last edited by 1983G20Van; November 13th 2021 8:27 pm.
1983 G20 Conversion Van, 350 TPI, Reed Hydraulic Roller cam, Ported 906 Vortec, Edelbrock 3817 TPI-Vortec Base, Doug Thorley Tri-Ys, Dual 2 1/2" exhaust, Speed Density 7730 ECM tuned by ME, 700r4 by ME, Stock 1,600 rpm converter, Rebuilt Stock 10 bolt with posi by ME, 3.08 gears, 358 RWHP @ 5,200, 384 RWTQ @ 3,400, 14.66 @ 95.43 w 2.28s 60'