Alan...Can't comment as to an originals availibility but, there have been and are knock offs avail today....I beieve the Roush 427 you refer to is a W not FE? If so bellhousing would be an issue and even if you are marrying to an FE I believe a special bellhousing is needed that leads to need for special dry sump pan, special clutch and slave and it goes on.....Also spares and repairs become an issue.....I'm told and based on Lloyd of RBT, Pantera experiences and Olthoff thrashing his 500+ HP/Tq GT that the new M type ZF that is built today can take it BUT I would be leery of slicks....I'm doing an FE w/ new ZF and feel OK....Steve