wheres the best place to buy new blocks.

be specific.
depends on what you want.

GM std deck 502 block?
GM tall deck/bowtie
aftermarket std deck
aftermarket tall
Aftermarket tall w/raised cam

not trying to nitpick, but it really DOES matter.

Your mailbox is full, PM me when you empty it.

Look at ebay Dynoflow reaserch.....search 540 short block I cant remember what he was getting for just the blocks....

i have lunati cranks, eagle rods,crane full roller cam, etc.
looking for blocks standard deck ,factory or merlin, dart.

If you're going standard deck, there's not a whole lot of reasons to spend more money than you'd spend on some worn out 502's and have them align bored and punched .030"

At least that's my thoughts.
Some old tired worn out 502's. Just make sure you magnaflux the bores for hidden cracks and check the valley near the lifters for evidence of freezing. Otherwise the MkIV or Gen6 GM 502 block is good stuff.

Johnny your mailbox is full again so I can't answer your PM.

PM me when you clean it out .

Yes, you can use Gen 4 cranks in Gen 5/6 block there are adapters for around $50 I have a few and I have used them with no problems. Until about a year or two ago that was the only way to use aftermarket cranks in the newer blocks now the aftermarket companies build new style cranks.