Old School vs Magnum on 86 Dodge W100

Please define "cam is bad".

No offense to the op, but I see a lot of generalizing in your posts, and lots of conclusion jumping. I see that you're here to learn, so please slow down a bit.

On the cracked heads, buy engine quest heads and be done with it. I would recommend this even if yours weren't cracked yet. If you can't afford them, this is the wrong sport for the team you're betting on.

Whatever you do, if you aren't running the factory efi computer or some other rev limiter, you need to upgrade your valve springs. Magnums have a VERY low rpm limit and will float valves. This results in bent valves if lead footing is involved.... ask me how I know!

That Magnum motor is, imo, better than the 318 in every way. Don't forget an electric fuel pump if it wasn't mentioned elsewhere