I am about 400 miles away. If warranty is not going to be covered, your best bet would see if one of us can help you. We have several 350's sitting around, but none of them in running condition. We could freshen up a short block for you for the cost of materials, and you could use your reman heads, intake and carb. Somebody else may can help too. 350 engines are pretty cheap if you can find one. Good luck and sorry about your problems.
Here is a 350 not too far from you. http://www.searchtempest.com/result...eytype=all&search_string_neg=&sortby=distance
Get on craigs list, find a used running 350 and drop it in. These engines are very cheap and often found in good shape.
I agree with Golden Oldie 65. Did you check your coolant level when the gauge was jumping around? I made a similar mistake once, the temp idiot lite came on and steam started coming out of the hood, then just as I was about to stop & check things out the steam quit & the idiot lite went off. I mistakenly thought things were OK. A few minutes latter siezed engine, lesson learned. If your engine did overheat & sieze then I wouldn't use any part of that engine as they might be warped or damaged. probly your best & cheapest option is a used one that you can hear running. Good luck with the car & nursing.