Where can i buy a 4 bolt main lt1 bare block?

 

I think the only LT engine that is 4 bolt mains is an LT4 block. Unless you can find a splayed LT1 block

 

f-body = 2 bolt

Y-body = 4 bolt

 

Since GM doesn't make LTx blocks any more, you are limited to finding a used Corvette block (or an F-Body that got a factory warranty replacement block). Or, have a 2-bolt block converted to 4-bolt mains, either straight or splayed