Demon 340 wheel size??

My Demon 340 has the 5 x 4 bolt pattern with drum brakes. I thought the 340 cars had 5 x 4.5??? What would I need to replace to end up with the 5 x 4.5" I am looking to put larger wheels and tires on the car. If I have to spend the rubbles, should I invest in disc brake stuff while I am at it??
Thanks