I need some opinions from the case collector world, I have an original 970 demo black Knight the engine is plain wore out and needs a major out of frame overhaul, new injectors, rebuilt heads Iam sure will also be needed. We all Know what this will end up leading to in cost with todays prices. I have what I think is a very good engine out of a 1973/1974? 1070 with a bad trans, I am thinking of just swapping the engines out to have a good running tractor again and cut cost, but I am afraid by doing that it will ruin the value of my original 970 demo versus just rebuilding the original engine. What do you guys think? Please be honest and have opinions. If something like this was on a sale and been changed would it hurt the value to you? Thanks for any help