Dont know , but....

I remember a few years back seeing a bare block on ebay , it was supposedly from a big name racer whos name I dont remember right now . it did show pics in the auction of some stampings including a stamped H M corporate style logo. I would look for that H/M stamp if its claimed to be a H/M motor. Probably would have started life as "the pick of the litter" but would have been driven hard as well .. only an opinion ....