I want to upgrade to the small Denso style alternator on my 1970 Dart, but my current setup uses a dual groove v-belt alternator pulley. Anyone know of a specific application where the alternator came with a dual groove pulley?

88 and 89 Diplomats, trucks too I believe

The trucks did use a dual groove pulley but some of them(maybe all) are really deep. The higher the amperage the deeper they are. I tried fitting a truck unit to my small block and it was so deep that it touched the head. You could probably make it work by spacing out all the brackets and the water pump/crank pulleys. Not sure how much room infront of the fan you have to move it forward. I wasn't aware that the Diplomats had them. If that's the case, you might be able to salvage the entire pulley system off of one. If you find something that will work, please share it.

I ended up using a reman Toyota piece. It's a lower amperage single groove.

Toyota Land Cruisers had dual v-groove pulleys.

You could always buy the alternator you need, then buy a pulley that'll work. Powermaster should sell 2-groove pulleys that'll work on denso alternators.

Are you looking at the small block 60 amp Denso kit? I had one on a 360 and it came with a single groove pulley. You can actually run a belt from it directly to the crank pulley by going under the water pump. Some of the earlier water pumps had reinforcement ribs and would need one of those ribs notched.

We've used the truck alternators on cars before no problem but have always swapped the bracket along with it. The bracket on M bodies also changed for 88/89 so that might be where fitment issues come in.

Mancini Racing has everything you need. Brackets, Denso alternator and belts.