Heads are in the shop right now. Resurface and valve job just to be safe. I'm scared to death of putting this thing back together. This is obviously my first time and i'm unsure about a few things. What has to be replaced and what should come directly from Isuzu? I've heard I should replace the head bolts (Isuzu only), timing belt tensioner (Isuzu only), timing belt (Isuzu), water pump (aftermarket), and the gaskets and seals (head set) (Isuzu). Do I really need to replace all of this? Can I reuse anything? Does it all have to be Isuzu? Also, how should I clean the brown/black junk on the inside of the intake manifold? For that matter, how can I clean the inside of the cylinders without pulling the pistons? Money and time are quickly running out, so please help me out.