Generation IV Internal Engine - Lq4 or Lq9

What is the largest bore and stroke crank you can safely put in one of these blocks?

.030 over bore 4" crank is your best bet, and just get as good set of heads as you can afore, they will make up for the rest of your anxiety's.

Agreed, while you can put a bit more stroke in it, with those relatively short sleeves I prefer to stay with the 4.0" stroke in those blocks!