Rob, the big thing to take into consideration is the saleability of the vehicle. Some day you will want to get rid of it and move on. A carrier with many modifications does not have the value of a pristine restoration. No one wants these clunkers for hunting camps etc anymore because of the snowmobiles,ATV's and such.
Now having stated the sensible part, I could easily consider a re power. No one can see under the engine covers in a parade or static display. I have owned a few stock carriers and I had a friend with a 289 cu in Ford engine with auto. transmission in his carrier. Boy I'll tell you his was a lot more fun to drive and it went like stink. We had great fun with it. We could go through a marshy spot close to his place, so fast that the beast didn't have time to sink in. We buried a half track in the same spot so deep we thought it was going to be there forever. Also have you considered a Mercury engine. 255 cu in. of Flatty with a top mount distributor. Put a 283 Chev carbbie on backwards and you are good to go. At the end of the day it's your carrier and your decision. You won't be able to please all of us.
Barry
