I used to have a 400 hp 340 in my Duster, with a high stall converter and 4.10s. And it was barely in the 12s.
I think you had some factory freaks that you never should have sold lol.
I saw a "built" 340 in a Volare with 4.11 gears and high stall go mid 14's. Yep, fender to fender with my 318 dart. I had a mild 360 in a 74 Dart Sport with 3.91's go 12.90's, and nope, it wasn't 400 horse.
