5.1 gears, anyone?

I had a set of 456 gears with a built 273 and a 4 speed in a 66 barracuda I used to own and it was wound up pretty tight at the end of the 1/4 but it was in the mid 1980s and I cant remember the size tire I was running but it sure did make that barracuda a quick ride only problem I had was push rods blowing through the the rocker arm twice from the high rpms,,won a lot of money street racing that car in sw fla back then and wish I never sold that car oh well