I'm looking at buying a 1980 Chevy K20 Scottsdale with a 383 stroker. The truck is in overall good shape and I have known the owner since I was a kid. The main reason I am buying the truck is it has a snowplow already on it. My only concern with the truck is that originally it was a long-bed and he shortend the frame and replaced the bed to make the truck a short-bed. Is there anything I should be worried about?  

as long he did a good weld job and made certain the axles are paralell to each other  

I did the same to my ´80 chevy truck,in order to use it as a hunting mule,chop the frame from 133 inches to 117 and cut the bed too,the frame was cut at the middle of the cab door,aprox.   in a (z) shape,rewelded and reinforce with 30 in. of (C) shape metal. I exchange the frame from that point forward with my ´82 suburban 4x4,since then the sub was lower,automatic (350) and useful for all my wife pregnancys(3)and family trips. And the ´80 pick-up is an every day farm ride,hunting on weekends,farm tractor extractor,it rains a lot around here,fishing boat tow vehicle,is now a manual 465,NP 208 and dana 10 bolts front & rear,15x10 chrome wheels,& since 1995 a bunch of set 14.5-33-15 mickey thompsons,12.5-31-15,12.5-35-15 all terrains,mud terrains,& the new ones 12.5-33-15 remingtons so check the welds,reinforce it if needed and go plow,i did myself & not a single crack has appear,have fun.  

Like the others here mentioned about checking the welds and that the rear axle is true to the front axle. You might want to make sure the rear drive shaft ( If it's not a 4-by - I'm not familiar with the Scottsdales )  is balanced if it was shortened, or just replaced. and that the U-bolts are still good.

Personally, the main reason I would have got this truck is for the 383 stroker! The other issue with the plow, you may need to add some weight plates on the back if you notice you lose traction. I drove a Ford F-150 fleet truck years ago and the tail would come loose pretty often, especially in the rain, or snow.

Hope this helps ya some.