I know I’m late to the party, but I had the same question about two weeks ago, I followed the advice given on this website and bought a 3500 9 1/2” stall converter from Dice preformance converters in Southern California I told him that I was going to drive it on the street and strip so it needed to be tight, but I wanted it to flash 3500 minimal, it’s now in my 74 Duster with a 360 magnum in it, and it launches like a bat out of hell. I’m glad I bought a higher stall converter that was suggested to me. It drives nice on the street too. And I have 3:91 gears.