I have run my 68 charger for 3 years with toyota alternators. I burned one up and had to buy another.
I ran an electric fuel pump, electric fan, msd, stereo, etc... and still had problems with good idle voltage. Everything would be fine until I turned on the A/C which would automatically turn on the electric fan.
At speed I was fine but not at idle.
I installed a powermaster 140 amp gm style alt. 90 at idle. Which is what I installed 4 years ago on my 67 Coronet which has a bigger mercedes electic fan and msd atomic system and fuel pump plus A/C. Never had any inkling of a voltage problem.
While the toyota alternators worked ok they were always working hard which isn't good for the life span.
Using a higher amp alternator with an easy duty cycle or load will make it last longer.
I do starters and alternators for a living (sad I know) the Toyota alternators (Denso) will out last the Delco style. Maybe you got poorly rebuilt or needed more amps then it could give. But by far the Denso will out last in it's amp range. You step a Delco up in amperage it will shorten it's life even more. The later style hair pin Denso are light years better than either, but the price reflecks it. If I was looking to put a 140 amp alternator on a hot rod and make brackets, I would use this off a John Deere, factory 140 Amp (which really charge more), much power at an idle. You can put in 1 wire regulators, use normal, GM and Ford Pulleys. If you want the advise of someone that sells thousands of starters and alternators a month, here it is
