[blykins]

For 302 based engines engines between 400-450hp, I don't use main girdles. A good set of ARP main studs seems to do just fine. When the engine comes close to pushing 500hp and/or turning some high revs, then I do what I can to stabilize the bottom end.

Four bolt caps in a small block really isn't accomplishing much. As some of you have pointed out, there's really not that much material there and you take a chance of just making things weaker. As a matter of fact, 2 bolt Cleveland blocks are preferred over 4 bolt Cleveland blocks. This goes the same with 2 and 4 bolt Chevy 400 SBC blocks (unless they're aftermarket).

On a skirted block (like an FE, LS, modular Ford, etc), crossbolted main caps will significantly add strength and are a good idea.