Info on avail. of 17" inner tubes????

[C5 Longroof]

I have a pair of 1989 17" Vette rims that I had narrowed on a lathe from 9" to 7" wide to fit on the front of my '67 Chevelle 2-door Wagon Pro-Touring project...When the guy welded them back together he somehow managed to get a string of pinholes on the inside flat section that doesn't allow the tubeless tire to hold air...He cut the rear 9" rims and extended them 2" to make them 11" wide and both those hold air fine...

I've tried all sorts of sealing methods but just can't seem to get them to be safe/reliable in my book...

My first thought was to just throw a set of tubes in there, but I haven't had much luck in my searches finding any kind of high performance 17" tube with a regular stem...All I find are the 17" truck tubes with the 4" long stem for use with dualies, etc...

Has anyone else had to deal with this?...

The guy that did the narrowing has long since moved...

Thanks Guys!!