You probably have a dealer add-on a/c unit. I have worked on a 76 or 78 G20 Van and it had an orifice tube. Right where the metal hard line liquid line runs into the evaporator inlet. The evaporator on a van with stock air is under the hood.
Last edited by 1983G20Van; November 18th 2019 8:57 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'