I wouldn't use the SM318 behind any thing much more than a 283 unless your very easy on the pedal. I replaced the sliding gear 2 or 3 times in a 64 Impala with a stock 300hp 327. I'd look for a latter all synchro 3spd. If you still have the stock rear axle find one with the overdrive.

Larry


I don't own a vehicle that isn't old enough to drink.