3G Alternator Upgrade - Needing 3V Crank pulley

[rbmgf7]

I managed the 3G swap with ease and went ahead and purchased a 2V pulley for the alternator but still running the 1 belt off the crank.

I fired-up the truck but it whines real bad throughout; not just on startup. I guess it has to do with the 8 inch stock pulley diameter. Seems like it needs to be reduced.

Can anyone suggest a 3V 4 bolt crank pulley for a 302 in a 1970 F100? I see a bunch on CVF Racing but the diameters are all the same for all 3 grooves.

[aquartlow]

I also run a 3G and my crank pulley is 7 5/8" without an issue but I only turn 5500rpm at the most. There are different sized v-belt pulley's. may want to try a larger pulley if you feel the alternator is turning too many rpms. I modified my 460's crank pulley to accept a 6 rib pulley to run the 6 rib pulley on the 3G, got totally rid of belt squeal. Luckily the 6 rib and my 460 crank pulley had the exact same diameters, making the conversion fairly straight forward. Good luck.