Crank Hole Finish Size For Pilot Bushing

I've posted this on other threads about drilling a cast crank to accept the 4 speed imput shaft. I can be done but there is a risk. I lived through the following ordeal so it's not a myth!


This might be a stretch. But when you pull the motor stick your finger in the back of the crank thru the pilot bearing to see if you come up with fresh oil. If you have a cast crank it could be forced thru the casting. Years ago Wheeler manufacturing had the bright Idea to drill the back of the cast cranks in there 400 BB so they could be used in a auto or stick aplication. The problem was that the cast cranks were to porous and the oil would go right thru the casting and out the drilled hole. I found this out after installing one of these and pulling the pan twice and the auto trans 3 times. For me it was an easy fix i cleaned the crank real good with carb cleaner. filled the hole with JB weld and put a flat expansion plug in the center. Yours with a stick might be harder, if it turns out that is the problem.