So I can't get the lower bolt out on my '88. Had a 1/2" drive breaker bar on it and heated with a propane torch and the bolt head is starting to round off. Wouldn't budge a bit. Any thoughts? I have to fix asap as this is my plow truck and the battery only lasts about 10 minutes plowing.

 

A good penetrating oil and several days might work.
Heat and a small hammer.... cook it then tap away at it to jar the corrosion loose will likely be a slow process but faster than p/oil.
Footnote...
I have replaced WD-40 and several other light duty oils with "Rust Check" in an aerosol can. Today, in under 10 minutes, I was able to get one nut to loosen up and come right off when removing the air filter box on the Lincoln. (that's the short story)
Can you get any of that Sea Foam?
Here's something that we have to do to our equipment once in a blue moon....
Tow truck self loading dollies are just a set of simple levers. When badly neglected they will seize solid. We heat them up real good with the torch and use what ever is most convenient for moving the lever (5 foot bar usually). For every fraction of an inch that we can break loose, we BLAST the hot steel at the joint with WD-40. This produces clouds of smoke and is better done outside.
So, if you can work the alternator with a bar like you're tightening the belt and cook it good and blast the daylights out of it with WD-40, you might have it cracked withing 10-20 minutes.
AL.

 

Thanks for the replies. I will give it a shot tomorrow. Today I only had time to finish plowing after charging the battery last night. Work gets in the way of all my important projects!

 

50/50 mix of acetone and atf is a good penetrant. Irwin makes some sockets that work like ez outs to get off rounded heads. Beats the heck out of vice grips. I use mine all the time. Bout 20 bucks

 

You need to take everything off the front of the vehicle so you can easily swing the alternator. Basically wiggle it back and forth and bounce it around. Try to get some PB Blaster near the back. Then take the bolt off with an impact gun while rocking it back and forth. This usually will require taking out the radiator. You can leave the fan.

 

I had this problem recently, it took plenty of persistance and WD 40
I found the rear bolt the most difficult since it just spins and won't budge..