The original block should work fine as long as it's in decent shape. If you're not using very much oil, it's likely that the cylinders are still in good shape. In that case, you reuse the stock pistons with just a good hone job to re-thatch the cylindar walls.
Some people argue that the used blocks are slightly stronger anyway because of the repeated heat/cold cycle effect on the iron.
--nathan
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--silver_pilate
'91 GT, Built 306, Wolverine 1087 cam, ported Windsor Jr. Irons, and all the goodies...click the link to the left to see a full list of my mods...
Tried and True 302 Being Built to Outrun You! heh heh heh...
--Texas Panhandle--
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