John;

I'd be surprised if those are available individually, but look/ask around...maybe you'll find them...else someone can send you one from a retired dist...OR you can make one up out of suitable material (must be stable, temperature capable, also able of withstanding medium voltages)...glass epoxy circuit board material (G10) in 0.062" thickness would be an excellent replacement material if you can get it in small qtys without copperclad...I also suggest replacing the paper insulator strip with 0.010" G10 while you have that bolt assembly apart...nonfailute and absolute reliability of this assembly is critical to reliable function of IGN sys obviously...I also suggest augmenting the centering function of the shoulder washers (whose shoulders may have worn away to very little at this point) with a centering collar cut from a crimp terminal (thickness of dist body only!) and assembled on the bolt...replacement of all these insulators (who have served well but have probably earned retirement and replacement with modern materials at this point) will assure centering in the dist pass-through hole and also help guarantee absolute reliability....

If you can't find material, contact me off-line, I'll make you up a dist rebuild/insulator upgrade kit of aerospace materials...cheap!

Cheers