My 8BA block is missing the internal crankcase breather tube. This is the standpipe that fits in the floor of the lifter valley (1-5/16" hole) and runs up to somewhere about the level of the intake. Since I don't have one to measure, I'm looking for dimensions that it needs to be so that I can fab one up. There doesn't seem to be a source for a replacement, so necessity being the mother of invention, etc. I know it's supposed to be there because my "build books" show installing it back in the motor. Any help?