The small journal crank flywheel flange is completely round, where as the large journal flanges are made with a counter weight.
Be careful with milling the pistons: Factory 302's had 11-1 pistons that could be milled flat. You must check dome thickness before milling, because different production runs of the same piston are not alike. You might have to mill 1/2 of the dome and install 76 cc or larger heads.
Good luck Mate!