It pretty much depends on how much load you gonna put on it.
If you keep everything stock, you should be fine, but if you have just one powerhungry deice like an electric radiator fan, than you need to go a different route.
You could use a shunt though, if you want to keep the original ammeter.
Whatever you do - make sure the power sensing terminal of the alternator has a wire all the way to your starter (where the positive cable from the battery connects).
And than there is also a more "fancy" hybrid shunt solution to this.
Here is what a friend who is really into this electric stuff was sending me a few years ago:
The best method when using an alternator is to make a "Hybrid Shunt" wire that bypasses around the ammeter.[Direct from the Alt to the Batt]
The Hybrid Shunt uses 2 "forward drop diodes" in opposing directions [parallel in this wire]
This is needed to get flow in both directions [charge and discharge]
The diodes have a fixed value of voltage drop to open them, whereas the ammeter [acting like a resistor] has a progressive/non-linear voltage drop.
Below 30a there is less voltage drop across the ammeter than what is required to open the diode, so the ammeter flows current. [The path of least resistance]
At about 30a there is a point of equilibrium where internal resistance in the ammeter starts exceeding the forward drop value of the diode so the diode will flow the excess current.
This ^^^^ usually happens when the ammeter is "maxxed out" on its scale. [after cranking over an engine]
Once the battery recovers [enough] and the charge starts dropping off the ammeter reads as normal
Use 2 x Vishay 150a rectifier diodes connected together parallel [back to back] mounted inside an old regulator box.
These have a 1.13v forward drop
The diodes behave like an electrical "pressure bypass valve".
Also if the ammeter totally fails this will not leave you stranded on the roadside because All Voltage will flow through the diodes.
To make the shunt Mount 2 x Vishay 150a rectifier diodes back to back on a piece of phenolic plastic [using common studs and spacers] Then mount a wire with eyes each side on the studs.
1 wire to the Alt and the other to the Batt.
Hide the diode board insde an old "period correct" regulator box. [you should have one left over from the internal regulated Alt Conversion]
Summary
99% of the time your Alt is discharging/charging in the -30a to +30a range and the ammeter works perfectly as original.
When there is a massive load or charge beyond the range of the ammeter, the shunt opens and flows the excess current.
Frank
