I've got a full roller 331 using a Dart block and world windsor lite heads using the 303x in my summer driver mustang. If I were to do it over, I'd build it as a 347 or even larger. I built it using a magazine artical as a guide. That was a mistake. Not much more torque than a stock stroke 302. I'm thinking of a redo and if I do it, it will be 408.