ok so... took the van for some time trials my best was a 15.1 with a blown power valve (or two)currently in it is a 318 that i built copying an engine masters build there motor made 415 hp and like 400 ft lbs so we will assume mine dose too the trans is a 727 tci strretfighter with a 1800 stall and a full race transgo shift kit in the rear is bone stock except new fluid im hearing its like 3.55 gears every one sayes the rear is killing me but before i toss a grand at some new gears and a limited slip im considering swapping in this mild rv 440/727 i have on the shop floor would the bigger motor make better use of the larger gears or should i still go smaller if so what would you recommend