I don’t have too much info on a friends Nash in a street-race 68 Camero (1970s) , 331 cu in modified production engine from Rhere & Morrison. Very high RPM engine, never really knew how fast because he bagged all the time looking for suckers money. 6.50s in the eight at will. Point is he never had a problem power shifting that trans in the 7500-8500 or more range. Can’t think of R&M drivers name right now who did the heads.