Along with rebuilding the L-81, I am considering  replacing the factory carb and distributor with pre-computer versions that are more tuneable to support the stronger engine.  Never bought a new carb, so can anyone tell me the difference in how the "electric" and "manual" chokes work?  Does the manual choke activate by a thermal coil and pushing the accelerator all the way to the floor and releasing, the same as factory?  What activate the electric?  Any other advise?  

A true manual choke is the variety with the cable run to inside the car somewhere, you can hide it under the dash so it's less noticeable. I'm putting one on an old Rustang I've been playing with.

I agree with Contrail, sometimes the electric types can be a little tempermental.

I have installed several aftermarket electric choke conversions.  Including one on my C3.  While I have seen the cool down problem, I have not had the problem.  My guess is either the choke coil is set too tight, or I have bought a better kit then some others.  I have bought the kits I use at NAPA.   You could also adapt a factory electric choke coil to a aftermarket kit.  That would solve the problem. 

Properly done, I prefer the electric.  Nothing wrong with mechanical or manual.