We have a 6-series Balmar 120A alternator on that engine
. For now, we are using the standard single
belt to run it. It will not operate at full load with this belt - I had to de-rate it down to 95A. I also had to change the pulley from the 2" supplied to 2.7" in order to provide enough surface contact area to prevent belt slippage.
Doing those two things, along with using high quality belts, allow it operate with only a bit of belt dust being generated. Also, it needs higher rpm to reach full output (because of the pulley change). However, this is not an issue for us because our alternators are a tertiary charging
source that are only in use when we are motoring somewhere.
There is no way you will be running a 165A alternator with a 2" pulley on that engine's single
belt. Even if you change to a larger pulley, you won't be able to get more than ~100A out of it - and that will be at higher rpm.
You will need a serpentine belt conversion. These are expensive - I'm guessing $700 or so. If you go this route
, then get the higher output alternator because that restriction has been removed.
I don't know about the AT series, but our 6 series came with a 1" bushing to make the foot fit the mount. This bushing was drilled for an imperial size bolt, and was too large for the existing bolt - it wouldn't mount securely. I had to make another bushing to fit the engine/bolt.
The alternator/crankshaft pulley ratio is what determines the alternator speed.