Core parts

I have a couple of questions for all you gurus.1) At the local core house this ole' boy has a set of 3 bar gt40's complete for $250, besides not having the relocated spark plug hole like the "p" heads is there a reason not to buy them. 2) He also has a couple of roller block 5.0. One of the blocks has a lot of oil sludge in the lifter valley, the other I can still see the lifter spider, my other question is if I buy one of the blocks do machine shops usually vat the block with all the lifter stuff still attached or can I take the them off and still get the lifters vated and cleaned? Or will it just be easier to dunk them in some carb cleaner. I was thinking about buying the block that was less sludgy. Thanks for any information.