I heard is was assembled by Leon Patton also. I know in the past he had the RCR motor which blew apart at Parker one year. It knocked a hole in the side of the block. Then I know the next motor was a Menard motor, that was the same time when Menard was also doing RGM's Cup motors.
Spenny Clendenen is the engine department manager at RCR but I don't think he builds any engines any more. If it's the best. probably Danny Lawrence or Greg Gunnell built them. Both are top flight. Greg built the engine that Dale Sr. won the Daytona 500 with. His dad is a good friend of mine. I'll ask him if he knows anything about the TT engine. He would have to ask Greg.