[blykins]

No, the deck will get machined down.

Sometimes the decks will be warped....sometimes they will just need a cleanup pass on them to take some pitting out.....but if you rebuild an engine and have all the machine work done, chances are it will be decked....even if it's a couple thousandths.

If your 289 has been worked on (chances are it has considering it's got aftermarket pistons in it), I'd say it's a very good bet it's been decked.

That will affect your compression ratio too....it's the same affect as shaving the heads.

Now instead of the piston deck height being .015" in the hole....it could be .010" or .005" in the hole.