I had a buddy in college that drove a '56 chevy with factory FI and he lost a plug on the injector housing one night, flooding the engine with raw fuel. He noticed the diameter was about the size of a nickel, so he put a nickel on a socket, put the peen end of a large hammer atop it and whanged it good, dishing it about 1/8". A little permatex on the lip, put it in place dished side out and hit the middle with a hammer. He never did replace it... Seriously, if you can find the right diameter foreign coin it just might work