Swaping PG for TH400 in 67SS Chevelle. I have read many archives and postings on just how much to shorten the drive shaft. Some say 1" others say 3/4". My calculations put it closer to 3/4". I suppose 1/4" doesn't make that much difference, or does it. Anyone got the straight scoop. Also, which length yoke to buy, Year One offers 2 or 3.