How much voltage is too much
The original coil was laying horizontal so I mounted the new one vertical,but after running a while the coil is very hot to the touch. should they get hot ?
All electrical devices run hot. That is a function of their very poor efficiency. Ever notice the heat being poured out of your lap-top by the tiny fan inside it?
How hot your coil gets, is a function of where you mounted it, and how well the case dissipates the heat. The factory location, IMO, is a terrible place to mount a coil. I'm pretty sure it was only put in that location, to save money.
The oil inside your coil is good for maybe 240*F. The coil is not "full" of oil, because there has to be room for expansion of the oil, as it heats and cools. If you mount your coil in a horizontal position/ studs down, that will keep the armature inside it "relatively" cool.
Your factory type coil with the transistorized ignition system, is designed to run at about 7 or 8 volts, thru the factory ballast resistor. You can run it on battery/alternator voltage for short periods of time, but it will heat up, and over time they have been known to fail. They don't always blow up; sometimes they just blow a gasket and start seeping oil. Occasionally, the armature wires separate from the studs.
Some guys, not me, have run their coils off a hobbs switch that switches from ballasted voltage supply to charge voltage, at WOT. Cool idea, but I didn't see the point in my streeter.
