Does anyone know off hand what the casting number is for a 4 bolt splayed block? Thanks in advance

 

The casting number is the same for a 2-bolt LT1 block and a 4-bolt LT1 block. They just drilled some extra holes in the 4-bolt block.

 

I have not pulled my pan yet, can the 2 bolts be converted or are new caps required?

 

2-bolts can be converted to 4-bolts by drilling additional holes. To convert, you need new 4-bolt caps. The factory 4-bolts were "straight" with nodular iron caps. Most aftermarket conversions (e.g. Pro-Gram) are splayed, with forged or billet caps.

 

thanks for the info