Drilling and tapping the crank for a SBC bolt is one of several minor operations that make working on a 216/235/261 a whole lot easier. By drilling/tapping the crank, you can use a stud/washer combo to DRAW the H/B into proper position, replace stud with SBC bolt and large washer and insure that it will remain secure. Retire the BFH!
Secondly, changing out the 2 lower timing cover bolts so that you don't have to drop the pan to remove the timing cover is, in my estimation, worth the time and effort. Drilling the lower cover/block holes to 3/8" (liberal application of grease will catch chips)and threading the holes in the front main cap (removed from the engine) will eliminate pulling the pan to access the 2 lower timing cover bolts. You can get to all the timing cover bolts from the outside. It allows you to loosen/tighten the timing cover without pulling the oil pan. This helps insure that when installing the balancer, that the loose cover allows the seal to center itself on the H/B seal surface, reducing the chances for oil leaks.
As long as you are going through all the effort of pulling the sheetmetal to correct the balancer issue, it just seems to me that insuring that you aren't going to have to repeat the operation again, makes sense. This would especially hold true if there was some issues with the crank snout. An H/B with a bolt is not going to do any walking.....period! As with any operation on your own vehicle, it's your call. Just thought you might be open to some options.
Dave
