Got a question about a OM603 head
 

So, I'm replacing my #14 head and I'm installing a #18. Got the bolts torqued, went to install the front 2 internal hex bolts down by the timing chain, and the #18 head is thicker, so my old bolts won't work.
Does anyone know the length they need to be?
Thx.

Are you sure? The 2 bolts are 1" long at least. Cannot remember. I doubt the #18 head would be so much thicker than the #14 head.