how to muscle up a 400 sbc

Just bought a 400 sbc with 90,000 miles on it for my 86 camaro. the engine came out of a 91 pick up. Before I install the engine, what can i do to increase the performance of the engine?  

Its a basic small block, except that any cylinder head needs to have steam holes drilled into it (get 400cid head gaskets, to use as a template) and the connecting rods are shorter (5.56 versus 5.57 inches).  

Pick a cylinder head, a cam to match it, and an intake and exhaust header package legal for your state.  

5.565rods (factory sbc400) vs 5.7 rods any other second/3rd gen sbc  

now that I'm not typing the answer at work....
Find out what exhaust is legal for your car.  That will be the breathing restriction on an engine 50cid larger than anything planned for this car by Detroit.  Cam it, and "head it" according to what the exhaust will flow out of the engine.  then gear the rear axle according to what cam you are running.  Engine tech in 1986 was to make torque from idle to, say, 4500RPM.  So, you may find sticking with "highway gears" and designing that 400cid to work within this RPM spread, to be the ticket.

Edelbrock, and others, offer head/cam/intake packages designed to work together. Or just pick one part you like, and ask their tech line what else goes along with it. Check into GM's optional 1LE brake packages, or Baer or whatever fits your budget. Z28s did come w/ a cowl induction package, or design your own.

your generation of Camaro was the first to be designed from the beginning to be a Z28 suspension, while others prior were designed for the 6 cylinder first, then attempted to make handle.  So, you shouldn't need a whole lot to get this car to handle the power you can make...and there's plenty of companies willing to help you go wherever you want to go with this car.