Thought I'd share this info. Stuck a 3.4 in my 88 that had a 22RE. My alt hits my steering rag joint with the stock belt.
Stock belt is 42" 4PK1050
I ran a 40.5" belt and it slips over the pulley at the minimum adjustment. No mods to the alt bracket at all. Plenty of room to clear my steering even after adjustments for stretch.
NOTE: THIS IS FOR REAR SUMP PAN. Front sump dip stick MAY interfere with how far the alt moves. Check before buying belt. Check www.crossbelts.com
for other options.
The shorter 40.5" belt I used is a (Bando) 4PK1030
88 Pickup, 4"SAS, R151F Hybrid, HP Front, V6 Rear, Aussies, 63" Chevs, Warn 8274, Bumpers and Sliders, 3.4 Swap and Dual Ultimate.