Tranny doesn't fit, now what

It's not all bad. Any A833 gearset will fit into your case. A 4.80" bearing retainer will replace your 5.125" one. If you do that you will have the equivalent of a "Hemi" 4 speed (with the exception of a 23 spline input) and you won't have to machine as much off the scattershield tranny bore. Plus you can choose the ratios you want. Being a '76 it should be a cast iron case, I know mine is and it was assembled on April 24, 1976. Food for thought.