If you are running an external voltage regulator (mechanical) you might want to swap over to an internal regulated (electronic) Delcotron. Started comming out in early '70s, all were by '75 when HEI came out. HEI ignition modules don't like voltage splikes!
X2 or convert to a late model alternator - they are much more efficient. An 80 amp CS style alternator is about 3/4 the size of an old 40 amp external reg. alternator.. wreckers are full of them. The front pulley swaps easy to a V belt. Locally the cost of a late model alt. is $10 more than ext reg. which have to be ordered in.
