I would recommend the Scat 4340 I-beam with the 7/16 cap screw they are about $250 and rated at 700hp. I have a set in a 377 now and have had no issue's. I recommend comp cams 306S cam it has 260 dur and .555 lift powerband is 3-7,000. Great Cam and its not a roller so it keeps the cost down. also that 377 has the scat 9000 series crankshaft too. 8)