I was wondering of the L18( aka 8.1L ) block be used as a base from building a motor
for a fbody or ybody? Would a 4.25" LS1 crankshaft be able to be used along with LS6
heads? It would be nice to be able to use that 4.25" bore as a starting base <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

No, the 8.1 block is not based on the LS1. To the best of my knowledge, the 4.8/5.3/6.0 parts are not intercangable with the 8.1.

 

Darn, a 482 CID would be nice <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

The 8.1 uses the basic architecture of the Mark IV Big Blocks with LS1 style parts. Therefore parts are not interchangable with the LS1 derivatives such as the 4800, 5300, and 6000.