Oversize valves?

There are no CHEAP oversize valve setups anymore, for the slant. Engine Builder was one supplier, for "drop in" pieces, but he retired. Also SI Valves, but they have discontinued them. Most slanters now, are going to the small stem metric valves, but that requires replacing the guides. Or you can get valves with the 3/8 stem, with the correct length, and have the head diameter cut down.