If you are running the original alternator then yes you will need to change it as it will be a 35A version. The bonus here is a VN alternator will almost bolt on. Depends on the version of your housing as to whether the VN will just slot in. If not and it is a bosch then you can change the guts of the 90A VN one into the older housing and get the upgrade that way. The other trick is I believe a Magna housing (from a mid to late 80's Magna) has an offset housing which can be used as well. This is what I used on the EH when I had it to actually get a 200A alternator into her. While the 200A was a brand new alt I needed to change the housing to make it fit and align properly.v6bucket wrote:I did notice that the volts appear low, the alternator has a large pulley on to slow it down a bit, it was bending the fan blades at high speed, I think I calculated something close to 20000rpm at 7500 engine rpm. I will investigate, I think the alt. is only a 35 or 40 amp unit, the voltage at the battery is ok, will check the connections that feed the ecu, might have to fit a bigger one.
Regardless the way you go, you will need to remove the front pulley and put it on the replacement, as most of the newer bigger alternators are a serp belt not a v belt.
Cheers
oldn64