[nutbush]

Will parts from all 350 sbc's interchange with other sbc's?

Like would heads from a '63 sbc 327 fit on a 350 block from say '90?

Basically are all 350's the same deck height and will accept all sbc heads?

thanks for your help!

[DoubleVision]

I'll answer your questions in the order you asked.

Yes the 60's heads will work on the 90 block. However the 60's heads do not have accessory holes so modern brackets won't bolt on. Also they do not have hardened valve seats for use with unleaded fuel.
All generation one small blocks are the same deck height of 9.025 and all generation one heads interchange. You have to be aware of chamber sizes. If you were to bolt 76cc chamber 350 heads on a 305 it won't have enough compression to spin on ice.
As for the deck height, thats in factory figures, when it's checked it's just about always off due to the decks being tipped, tipped as in one end is higher than the other. However on the interchange be aware LT1 heads from the early 90's on will bolt on to a Generation one sbc, but none of the coolant passages line up due to the LT1's reverse flow cooling.