Yes the 500 cylinders will bolt right in,but you also need the 500 head.
Essential the 500 is a FACTORY big bore 400.the only dif is the 500 cylinder,piston,head,exhaust and carbs that are diferent from the 400,both have the same crankcase and crank,and Y pipe.
Just get the Indy500 specs for your ste up if you go with the 400 to 500.
Punch Da Throttle and ROOST!!