347 Cranks, Stock block
 

I have been using a Scat cast crank in my 347 for about three years! This weekend at the races I heard a faint kocking sound with the trans in gear (c-4,) after a lot of checking I can move the crank in an out of the block about 3/8'', It still ran 12.25@ 111.4 on Pep boy radials and with good oil pressure. Anybody had any simular problems!