To get the period correct look I'm going for I needed to backdate a few things, and put together a v-belt style accessory drive.
Fortunately I had a 305 out of the '86 that I had just LS swapped, so I robbed that of its from accessories...I believe this is the last year GM used a v-belt setup. In fact they had already moved over to a modern ribbed belt for the 12SI alternator at this point. I debated moving to a 10SI alternator to get the open blade fan look, but having the parts in front of me encouraged me to stick with the better 12SI
As you know by '86 GM had moved to the R4 A/C compressor, so I found a set of A6 compressor brackets from a '75 suburban to use instead. The remaining missing bracketry came from an early 80s Buick I found in the local pick-n-pull. I sent all of the bracketry off to the powder coater to have blasted and coated. I know GM typically used gloss black in the engine bay, but I felt a slightly more matte finish would look better here.
The fast burn heads support both center bolt and edge bolt valve covers, which let me use the period-correct 70's stamped steel covers that I snagged off eBay. The intake that comes on the SP350/385 is a high-rise style without EGR provisions, so I swapped to a GMPP 12496820 low-rise manifold, which has the EGR boss and vortec-style passthrough.
For exhaust, a buddy had some freshly powdercoated replica cast manifolds for an early OBS truck, which are a better (but not perfect) fit for the large exhaust openings on the fast burn heads. He also had an extra late 70s truck air cleaner that I snagged, which got coated along with the brackets.