87’ Engine Retrofit 86’ Truck Issues?

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Have a 1986 chevy Silverado short bed 4WD loaded truck, 700R4, needs engine ( gone). Opportunity to buy 1987 tbi 350 out of suburban, again loaded engine including AC. The 87’ engine includes all accessories. Will 87’ accessories, e.g. AC bolt up to 86 truck accessories connections. 86’ truck has original engine bay wire harnesses, are they compatible to 87’ accessories? 87’ engine has 115K miles.
Understand need to change intake to carb, along with distributor/MSD. Will 87’ 350 block allow use of mechanical fuel pump?

As alternative have 88’ Blazer with worn out 350 engine can use for engine bay parts, choosing alternative long block.

Thanks,