i beg to differ.DO NOT over rev these engines.my dad converted an old 59 a160 bus into a camper and pulled the 6 and 4sd and added a 345 with an fmx ford trans.it ran great and loved running 50-55mph.but turn over 60 and it would break teeth on the cam gear.happened 3 different times.just came to the conclusion that it didn't like the 60's so kept it under 60 and never had any more problems.