If you need to tear that flathead down and have it rebuilt, you are talking in excess of $3000... not bad comparative to any old car or truck engine, just be aware. There are several engine shops around that specialize in antique motors.
As with anything vehicle related, I always insist that body is everything. The mechanicals are secondary.
Nice thing about cmp trucks is that there were plenty made and many of the parts are interchangeable. Fords rule BTW, forget that Chev nonsense Bob is speaking of-

216cid 6cyl Chev vs 239cid V8 Ford power, do the math...