Brad it is honestly difficult to put a price on it. The price or value is going to be different from the seller to every buyer that has the cash.

Couple things to consider;
You want to be absolutely sure it is a genuine Sandman
The motor not matching should not detract from the price, unless this is advertised as fully original/factory vehicle etc. If you are lucky enough to have the original engine then good but not a going to be worth $1000s more or less.
Paint can always be changed

Have a browse through our Sale section and see what similar cars have sold for and you will get an idea.

Sorry can't be much more help - others will chime in with more advice.