i chose and run a .040 over 351W.....nothing real fancy with Edelbrock RPM heads, hyd roller cam and dual quads.....the first tranny was a C-4.....one hit of the throttle and it lunched....bought an AOD from Hughes....best tranny and gears i've ever had on any rod.....the AOD is an inch longer or so....easy swap....coupled with 4.11's it runs low to mid 2k rpms at highway speeds and will wildly kick the tires loose....its not a vacuum tranny, the cable is easy to set....and it works great