i can tell you from experiance that ssre scott shafiroff are good people they are very friendly and if there is a question or a problem they will work it out i was in the same boat as you are i run a 468 and wanted to go bigger i build all my motors myself but i met a guy on this site from indiana we were talking he and all his buddies run 598s from ssre he assured me they are top notch people so i took his advice and bought a 540 bbc with dart big m block jessels the whole kit and kaboodle and let me tell ya what i could not build that motor myself for what i paid for it and let me tell you one thing a motor is only as good as the money you put in it you can buy a motor with srp pistons and ohio crankshaft rotaters for dirt cheap but dont expect to live very long an old saying is you only get out what you put in dont be cheap do it right by the way the ssre 540 put my 3640 lb car on the bumper and still ran 970 good luck