What would you do

I bought a 66 valiant last year out of a field. Paid little of nothing for it. Started to tear it down to restore it for my wife. I went ahead and pulled the /6 out of it and rebuilt it. I mean everything in it is new. It is sitting on the engine stand waiting on the car to be blasted. Tore the interior out and found that the floor pan is totally gone. Trunk pan totally gone. As you know being a 1 year only you cant buy these parts. I ran upon another 66 Valiant Sunday. Bought it. The guy told me it was a 318. Brought it home and found out it is a 273. Not running. I dont know anything about a 273. My delimma is do I take the time and money and build this 273 or do I just go ahead and put the /6 down in it and move on. I dont know if the 273 would be a better choice for the money or not. I know nothing about a 273. all I have here are slant 6's and a 440. what do you think. Thanks,Bill