Bolt and Nut Sizes?

[ryOs13]

Sup Guys,

I'm just wondering how you would go about finding what size bolts, nuts, or fittings are used within the engine (for example, wut size bolts including length are used for either manifolds, or some relief valve, and so on and so forth). Is there a p/n systen for this? Some type of search function? I'm looking at the FSM, and either im totally passing right by it or all it does is list torque specs and such. any help is appreciated.

Thanks