I have the first version which came out in 2017 for the M8 with the short filter. I see the new heavy breather has a larger filter element capable of more air. Does anyone know if that new filter will retro fit the older unit?
No, they are totally separate air cleaners/designs/part numbers.
To clarify, I think you're comparing the new Screamin' Eagle Heavy Breather Extreme that appears in the GMA20 catalog with the older Screamin' Eagle Heavy Breather Performance model that first appeared in the GMA17 catalog (and is still in the GMA20).
Unless i missed something the M8 heavy breather come with the small angled filter. The twin cam heavy breather and elite version filters do fit. I am not sure about the extreme model.
I think Fuel Moto sells a bigget filter for those.
Got a look at one of those Extreme filters yesterday, and I'm pretty sure they just ordered up a load of Duramax filters. It's big enough that it appears to need some kind of sling to support the monster. Ridiculous overkill.