I am building a resto-mod 86 Dodge W150 with a 318 and AC with double grove pully, have a bunch of aftermarket electrical items (2 fans, Holley TBI, Etc.) The factory alternator doesn't produce enough amps to charge the battery when the truck is running at idle with the items on. Was told that the alternator from a 93 would have enough amps and would fit in the factory location, but it doesn't as it is to wide to fit in the factory spot and the power pin is on the wrong side.(Denso 120 amp, 4130). Was wondering if anyone else has had this problem and if there is any alternator that would work, or am I just going to have to buy a custom one or completely make a bracket so the 93 one works it needs at least 100 amp at idle.
Thanks

 

have you checked summit? 194 results show up for a 86 w150 and most of them are over 100 amp. also you don't need 100 amps at idle. i would maybe say 50 amps at idle. you can likely get one that puts out that much but even the ones for the diesels don't put out that much at idle.
https://www.summitracing.com/search/...ord=alternator

 

I have checked summit and the problem is that the body of the higher amp alternator is to wide to fit in the factory location on an 86 with AC. I do need the higher amp rating at idle because with the holly running with the fuel pump and one fan on the 100 amp replacement only puts out about 50 amps at idle which isn't enough to keep up and charge the battery

 

sounds like you will just have to custom make a mount to make whatever alt you buy fit if your not happy with the alternators option available for the truck.

 

The 100 amp factory alternator back in the 70's had a different bracket(larger alternator). Not sure if it was offered in the 80's or the same type. May want to look in to it or mod the brackets you have. I believe there are also different size pulleys that can go on them, The smaller ones turn faster so it will put out more at a lower rpm.

 

but even then none of the factory alternators put out 100 amps at idle and any that put out that type of power won't be bolt in even with the larger brackets. might be able to get one that bolts into the 88-91 brackets but obviously they may be very tricky to track down and i don't know how they would work with a 86's factory a/c