I have a 3892657 engine block I am rebuilding (numbers matching) for my 67 camaro, 350SS/RS. The distributor tower that is cast into the block in the oil galley is the tall style. There is a 'sleeve' pressed into the distributor hole, and there is an angled (down) hole drilled through the tower from the oil galley into the distributor hole and through the sleeve. However, the hole appears to have been welded closed! I have a 68 block w/o the sleeve and the hole is open. Does it matter if the hole is open or not?