Im sorry but a 4cyl that has been converted, wears 5 lug discs all around, has a "built" motor, and
suspension could be viewed as better than a 5.0. You know for a fact if it started as a 4 cyl it was not beat to hell and back and then modded to look nice. A 4cyl and 5.0 are so close and once you replace the driveline they are the same car, only the 4cyl should be tighter! So long as the person knows what he/she is doing and does the swap right, I think its a mute point.
To me that car if it is as clean as stated is worth easily $7000-8000. New paint, wheels/tires, whole 5 lug disc set up, decent motor combo, and as clean as that. I think if most people owned that car they would say its worth $10K, but most people on the other side make claims like $4K... its a double edged sword! The sellers selling for too little, buyer paying too much!