I'm building some 502's useing all parts from my 454 mag's I'm told that the flywheel is different and the balancer,and oil pan is that true

Oil pan...454 prob a Mark IV while 502 may be Gen V or VI, they are different. Flywheel and balancer dont think so. If your 502 is Gen V/VI timing cover different, cooling passages on deck/heads different but can be paired with proper gasket, may or may not have mech fuel boss, crankshaft different, rear main seal two piece mark IV / one piece Gen V/VI...there may be a few others. You can check your block number on the internet to see what generation your blocks are

One thing about flywheel and balancer...internal balance and external balance...need to know what is what

Thanks guys

Are the 454's gen V or VI, or are they older MK IV's? What year are they? EFi or carb? These questions will tell what will work and what will not.
Eddie

The engines are 1992 Mags they have carbs and I call in the heads # and they are the same heads on 502's retangler port I will pull motors feb 15 and will know more I'm trying to build a little more horse power might build what I got depending on price thanks