I've got a 55 power glide 235 in my 52-3100 and did the Pre-68 Dave adapter and used a 216 water pump, I used the balancer off my 216 and used a 3/8s belt with no problems others here have also used the 3/8s belt with no problems,using the stock 216 water pump instead of the short shaft pump if you ever need a pump out on a trip you can order it from any FLAPS it's cheaper and most places can get one in 1 day.My truck is converted to 12volt alt. and the 3/8s belt is fine.
Pete
