Replaced voltage regular, good for awhile, now drivability poor
 

I changed the voltage regular in my 1983 911SC to resolve headlight/instrument panel surge. It was good for awhile (40 miles?) but now it it's driving bad. Bad stumble, on verge of bucking. Idle is ok, but soon as a load is put on the motor, things go sour. Any comments will be greatly appreciated.

My guess is the battery is still not charging. Do you have a voltage meter? Voltage at the battery with the engine off should be around 12.5 volts. With the engine running it should be between 13.5 and 14.5 volts. My guess is one of three things: bad battery, bad alternator or bad voltage regulator. Or you hooked the new voltage regulator up wrong. That would be one of four things I guess. :D