I put the new 60/120amp GM three wire on my 86  sammy. now i burned up the stock coil,,, wondering if bcuz i went form the stock 40/55amp  to the 60/120amp if i need to get a stronger coil, and if so will that be to much for the electrical system

It's unlikely that the alternator upgrade caused the ignition coil to fail - at least - not if it was done correctly.

The alternator should have a regulator that holds the output at a nominal 12V, and if the output was high enough to fry the coil, there would probably have been other electrical damage.

Once you've replaced the coil, you can check the charge voltage - which by the way, should have been done after the alternator upgrade - measure across the battery terminals, with the engine off you should see roughly 12V (+/- half a volt) and with the engine running that should jump to roughly 13.5V (again +/- half a volt) - the exact voltage will vary with the age and state of charge of the battery, anything above say 14.5V is cause for concern.

I've got 12.3  with engine off and12.8 running .just put in new coil and runs good..  Is 12.8 enough

should be a little more, you might have to move the voltage sensor wire to a different spot, like maybe the ignition switch.

Nope - I'd expect to see at least a 1.0V jump once the alternator comes online - so if you have 12.3 with the engine off, I'd expect 13.3 or more with the engine running - that thing is barely charging, and when you load it up it'll probably drain the battery.

Are you sure that alternator is working?

Thinking a bit more - the Swift should have a 65 or 70A alternator that bolts right up to that engine - with maybe a pulley change to match the belt type - have you considered that as an option?

The alternator is brand new . A couple of weeks ago my battery took a dump on me out on the trail and I had to keep using my jump box to limp it back to camp . Maybe  I fried the regulator . I'm going to have it tested. Bcuz when I rev up the motor the amps go down.. Thanks for all the input. I'll let u know what happens

You should see a 14.3vdc output from the alternator.

What model alternator and what is your connection scheme?

Take it from an old guy. I've learned over the years to have the auto parts store put the new alternator on their test bench and ensure it produces at least 14v. before I take it home and install it.

Yeah, the battery at rest should read at least 12v, more like 12.5v.

With the engine running, no accs on you should see about 14.5v after it warms up some and about 13.5 with lights and such on.