Opinions on value of '66 Valiant with 273 Commando

What do you guys think I should offer for a ’66 Valiant Signet two door hardtop that I found? I would like to make an offer that is fair for both the seller and myself but I’m not sure what a fair value would be. I know it’s all about the condition so here’s what I know.
Being sold by the original owner who ordered the car but it has not been running since 1978, he’s looking for offers. It has over 125,000 miles and still has its original 273 commando engine with the exhaust still, it even has the chrome tip on the resonator but it’ll need to be replaced. Other than the engine there’s nothing too special about the car

My 2 cents worth. Figure your bottom line for when you get done. You are going to invest a lot of money and saving any on the initial purchase will help, but not much at final tally. It's worth what he will sell it for and what you will pay for it. I would do a excel sheet with costs for paint, interior, engine rebuild, tires, chrome, rust repair, anything you can come up with. Show that to the owner and 1, he will know you are serious and 2, it will be a big number. Then if common sense comes in you can get it reasonable. I like a 66 and with the 273 4 Barrel it will be sweet. However, $500 to $1500 is all I would do. Parts value for old used parts is not great. You would be lucky to get $1500 back if you do part it. It would be a shame to part it out. Good Luck!