440 build for a tow rig/"muscle" truck?

Back around 1989 I built a 440 from a '75 Imperial for my (formerly 318) 1970 D200 Camper Special. The truck had 3.54 gears and tall 16.5" tires, so I figured normal car gearing around 2.94:1 as far as my cam choice. The 440 had smooth bores but signs of detonation (eroded piston tops and worn upper rod bearings), so I had a set of NOS 8:1 flat tops and a NOS cast crankshaft, and I used them with standard rings and bearings (full groove mains) and a HV oil pump. I had a set of 906s fitted with hardened seats and stock size stainless valves, with Street Hemi springs. For camshaft I went with the Direct Connnection 272/.455"/112LSA cam, stock TQ iron intake with the EGR blocked and floor jets milled flat, and a '72 Thermoquad. For converter, I used a 12" (narrow ring gear) factory unit for efficient cruising and low heat. It worked fantastic and I used it for some heavy towing and it was also my daily for many years. Around 1995 the Dana broke a pinion gear (punched it clean through the heavy rear cover), so I parked it until I could find a replacement rear end. The cheapest one I could find was a 4.10 gear, so I knew my gas mileage would suffer but the tow power would increase. WRONG on both counts! Same basic MPG and no noticeable breakaway acceleration loaded. 440s are just that tough and impervious!