Hey guys just wanted to test some brains out on here, ive been doing up a 4k motor and what ive done too it is as follows, Head shaved ported and polished, race cam thige 401, heavy duty springs, block decked and alligned and crank ballanced, flywheel lightened too 6 kg twin 42mm webers high flow extractors etc etc, now here is the question after spending so much time putting it back together, ran for bout 2 mins and stopped with a really bad graunching and died right then and there, will be pulling it apart tomorrow to find out what the cause is just wanted to see if someone out there could guess and see if someone gets it right ill let yas know tomorrow night so good luck guessing!