I used a system called the slim line in Debs pickup. We bought it at the Springfield swap meet from a street rod place out of Dallas. They're pretty much all the same. The one we got has 4 outlets under the dash and fits behind it really well. It went in easily and works great. I also got an Alan Grove bracket set to move the alt. to the drivers side, that made it much easier to fit every thing. We've had it 2 years with no problems.

'65 C-10, 65 L-60, 65 C-80, 72 C-60 & and a bunch of old Chevy cars.
Never time to do it right, always time to do it over.