Yea its not a good idea. You alreayd have a good foundation, just save up or go with a cheaper build. I lost my license which is why I am tearing down my car right now and rebuilding it. But when I first lost it I wanted to sell my car and do the same thing, by a roller and slowly build it. But I decided against it. First reason was because sure our cars may be WORTH a certain amount but try finding someone to pay it. I had my car on the market for a month or so for 3k and didnt even get one hit. And its not too easy to find a roller for real cheap. The way I saw it was I had a good foundation, I mine aswell part out the performance parts I have and go all out.
Like said before you are going to be spending money trying to get the car back to how you have it now.
Even if you do it and have an extra 2k to spend on the car, thats not gonna get you very far on a afr headed 347.
you may be able to by the heads, and the stroker kit and thats it. Now you gotta fix everything thats wrong with the car, and save up MORE money to get it done.