HELP! transmission case repair?

Not a welder? Moi?? I removed the head from a 250 ford inline six and saw that it had been recently rebuilt, but nothing had been done to raise the compression. .030 deep dish pistons. I ran two up to the top, loaded my trusty Northern Tools mig with aluminum wire, hooked up my argon, cranked up the wire speed to the max, and WELDED domes onto the pistons. No, SIR, I did NOT remove the pistons. I also did a Opel 1.9 the same way. They both ran like striped-azzed apes. But I would NOT recommend welding up this case. Cut it off flush and drill and tap. If the tap gets sloppy, use JB weld as a "sealer"...