no experience but found this https://www.forbbodiesonly.com/moparforum/threads/which-mini-starter-for-318-poly.191041/ confirmed with this https://poly318.com/poly-318-la-b-rb-slant-6-mopar-starter-motors/
I bought an after-market TCR? brand from a local Mopar specialist (will have to check the sticker on my tool-box) It gave trouble - loose internal connection or such and I went back to the OG as there was no problem with room or access in my car. I don't think it went back on the car, will check in my parts storage and come back. At least I've still got the "Highland Park" whine which I didn't know aboiut untill I read it on here LOL
I use a Powermaster on my Poly but I think most of those on the market are similar. However, there is even a smaller starter that will fit. Ask for one from a 2005-2008 Dodge Ram with a 5.7 and a MANUAL transmission, the automatic starter for this application is totally different and will not fit. The Ram unit is a coaxial (planetary) gear reduction design, not offset like the Chrysler and Nippondenso gear reduction starter designs. That's why the motor housing is directly in line with the starter drive axis making the whole starter more compact (picture below). Be sure and get a genuine starter with a Chrysler, Denso, or Nippondenso nameplate on it. Even a used genuine starter from a wrecking yard is preferable to a new fake/Chinese unit or any of the "remanufactured" starters.
Ahh yes . . . The song of the "Highland Park Hummingbird". I'm not sure I could even drive an old Mopar that didn't have the O.E. gear reduction starter.
I miss that "Highland Park Hummingbird" song so much, the last ride I had with the starter that made the music was replaced with a newer mini starter several years ago. I probably still have a few of the old used starters around, if anyone desires to hear the music... I only have one ride that still has enough space to put one of those monsters into, and I don't for see that happening.
The Jalopy Journal
