Just a follow up; Got the helicoil job done. Not real proud of myself on it, as I ended up a little off when I drilled and tapped, but afer dressing the gasket seat to match the off angle, it sealed up fine. I do plan on hunting up some extra cores next time I hit the salvage yards. Fortunatly, I have several in my area that do not crush old tin.

Bill Burmeister