if you are going all motor, go with the b20 since its already at 84mm and most of the b20's that have cracked were from forced induction. I'm sure you'll be fine going b20. LS bored to 84mm is like asking someone to nailing your ***** to a board--its pretty stupid.

 

If I were to go with say Benson sleeve's and bore it out it is tempting to go to say 85mm or if I'm frickin nuts to go to 86mm but I've heard that even with an all motor setup and especially one with High Compression anything over an 84mm bore in the Frank' setup's aren't hardly streetable. And since this is a weekend racer as well as a daily driver, I think I'd just stick to 84mm H.C.

 

you'll be fine with 84 or even 84.5... should have bought the pistons I had for sale earlier. Would have been PERFECT for your setup. Arias 84.5mm with Eagle Rods... <SHRUG>

 

86mm are more drag motors has there are issues with headgaskets popping

 

Just get the b20 and fill the block with devcon or moroso block filler.

 

HMT sleeving