I had a 3v71 I sold last year, because I didn't picture it in a truck. Now I see they were actually in GMC trucks. What kind of gearing was used? Were they as slow as I'm expecting? I have 87 GMC Brigadier with a 6v71 and it has a 12000lb front axle(need to sell it). The 6v71 is one solid chunk.
Stretch your frame and sheet metal or maybe move the cab back a couple of feet. Might be easier to add 600 to that 350 and restore a 950. I went to a truck show last month that had some beautiful GMC950's with 6v71 engines.
