[TR] Swapping TR3A block for a TR4(A?) Block

[Allan Reich]

Thanks to all for the answers re Steel Shim Head Gasket!  I don't think 
that's my problem now and am looking at replacing the block (which does 
have some cracks at the stud holes).
I have acquired another block from a club member ( Ser # CT25743E)   
which I think is from a TR4 or TR4A.  My block is TS65929E which is the 
block that came with the car according to the Heritage Certificate.
This new block is completely empty and rusty but looks ok from first 
check. Assuming it checks out with my trusted machine shop's validation, 
I would swap out EVERYTHING from my old block. Can anybody tell me what 
won't work and what I will have to acquire?
Allan Reich
Vancouver
1960 TR3A TS65713L (+O)