A real beauty, but not a 1958. Try 1957

If yours needs points, coils, condensers, impeller (the usual tune-up stuff) and also a pressure tank, that could cost you $200-300 alone. Adjust price accordingly. I’d also check compression before buying. It looks great on the outside, but I always rely on the old adage “let the buyer beware”.

That 57 Fisherman is in beautiful cosmetic condition for sure. The question is whether or not it’s mechanical condition is that nice also. Do a close inspection, checking compression, looking at the gear lube condition (will probably be dark brown/black which is OK). Have a close look for damaged/cracked castings that may have resulted from being dropped or mishandled. You will need to assume the engine needs an ignition and fuel system overhaul, as well as a new water pump impeller, unless the owner can show it was properly serviced somewhat recently. The final question is whether or not the engine includes a decent (not rusted) pressure tank.
My last question is how much do you want this particular hp/year engine? You would be hard pressed to find another one in such nice cosmetic condition. If this engine is a “must have”, then you should be willing to pay a little more for it. Does the owner have an asking price? If so, what is that price? Don’t insult the seller with a low ball offer, that might just turn him off to selling you the engine at all. You can use the fact that the engine will need a good amount of servicing before it can be used regularly. The lack of a pressure tank (or if its tank is internally fouled/rusted) is a great negotiating point also….