543 0R 505

I ve got similar pieces to put a 520 together, 4.375 crank, 7.1 rods. In spite of my favorite mopar builder/machinists opinion, i would use the best lower end bandaids i could get, to try to help the bottom end live. Im gonna use aluminum caps and a girdle. Not everyone can find/afford/justify the expense of an iron aftermarket block. Heck, is there even a new one available? Anywhere?
I can understand the expense if trying to go eights, but for a ten second car?