Very cool truck,Greg!
If you want to get rid of the tanker body,you'll need to learn what was carried in it last,is there anything in it now,is it a leaker,etc. Once you know these things,you can decide whether to sell the tank to a rancher or Construction Co. (if it's solid and clean inside) or cut it up and scrap it (if it's not full of explosive vapors). If it was last used to haul fuel,it can still be flushed and ventilated enough to be safe to cut on.
As for the wheels,Daytons are a good set up;if you have 20" wheels,you can upgrade to 22",they fit the same hubs. Regarding the safety subject,I've never seen a "widowmaker" Dayton wheel,I don't think they exist. These wheels rely on a smooth rim center to slide over the hubs,so a center-split wheel couldn't work on a Dayton set up. I could be wrong...
I'll be interested to see what drivetrain this truck has;should have a 302 (If it has a two barrel carb but otherwise looks like a 228-270,it's probably a 302-I think the BIG sixes have the carb and manifolds on the right side of the engine,and look much bigger than the 228-302.
Whatever happens,don't let that truck slip away from you!
Speed