Pro-Gram engineering makes some good quality caps. They have a website.
I made my own once for a 400 block. As simple as they are them companies are making some good coin on selling them.
Just to throw something out there, if you have to use someone to do the machining, and after the purchase of the caps, and by the time the rest of the machine work is done to make a 400 block decent... you'd be WAY ahead to just buy a Little M Sportsman block.... I think you can get them under 1200 bucks and they come with ductile iron splayed caps.
I made my own once for a 400 block. As simple as they are them companies are making some good coin on selling them.
Just to throw something out there, if you have to use someone to do the machining, and after the purchase of the caps, and by the time the rest of the machine work is done to make a 400 block decent... you'd be WAY ahead to just buy a Little M Sportsman block.... I think you can get them under 1200 bucks and they come with ductile iron splayed caps.