Your Vet has ben changed so much I wouldn't worry about the value.
I would get everything working right before I dropped in that big block.
Make sure the front end is in good shape and the springs can handle the extra weight of a big block.
I agree with the other guys it's a 74 with a 78 backend.
Find someone out by you that knows and works on Vets
Good Luck!

 

Looks like the nose has been done as well. '73 began the rubber front bumper. What ever year or years it might be, It's a good looking car and you can build it they way you want since it is already modified. Considering it is already modified, I think dropping in the BB can only make it better. Good luck with it and no you didn't waste your money. It still a vintage vette. Fix it, Drive it and enjoy it. Don't forget the wave.Cheers

 

I think a BB could only help any potential value. Like a couple of the guys have said, the car has been chopped up so much that original value is out the door. if you paid 3500 for it , and it doesn't have a rusted out frame, then you got a pretty good deal. That car would be a perfect candidate for a full out hot rod type project. Put a blower on it, cut the hood, put a custom interior in it, and don't foget lots of window stickers....... with a back window that big you should be able to get a good 1000 HP worth of stickers on it. ( for more sticker info see the thred "Engine Question")

 

Not sure you are going to be able to hurt the value of this car. The front bumper (& probably rear also) has been glassed in & with a '78 & up rear clip, it would be very expensive to put this car back to '74 shape. Judging by the rust on the turn signal and tilt levers and the winter wiper blades, I'm guessing this car came from the rust belt. Check the frame thoroughly in case it needs repair. You'll need to put big block springs in front and sway bars front and rear. The big thing is to do what you want and have fun.

 

Thanks for all the info guys . I guess its time to take the body off and get to it . I took a look at the frame it did not look to bad but i am going to blast and seal it. That should make it last