I also disagree that the CWP brushrolls are crap. I think they work very well on particular machines; in the end, it's certainly nice to see something modern available for a machine that hasn't been in domestic production in nearly 23 years.
I would not use a CWP brushroll in ANY Convertible earlier than the High-Performance models from the mid 70s. The earlier Convertibles don't have the amperage/wattage and motor speed to get the CWP brushrolls moving fast enough to
not get bogged down. For this same reason, I am also careful to not use any genuine brushrolls or replacement brush strips comprised of white or red bristles - as they are stiffer than the black bristles. The new, stiffer bristles were introduced when the high-performance machines came out.
Any of the High Performance metal-base machines, or plastic base machines from the mid-70s onward would be an ideal candidate for a CWP brushroll, in my opinion. But again, I would never recommend or even think about putting a CWP brushroll in any Convertible from the 50s, 60s, or early 70s - unless you install a later motor in an earlier machine*.
*I did this recently, having gotten the "formula" from Jeff Parker many years ago, I took parts from both a mid-60s Convertible (model 584), and a Decade 80, and created a souped-up Convertible. It made sense to combine some of the motor parts, and took a bit of rewiring to get it right. It works amazingly well, and the CWP brushroll holds it's own. I picked up the machine at an estate sale and it sat in the garage for a while. When I found a Decade 80 to part-out, I realized that the 584 was a diamond in the rough, under a layer of filth, so I got to work... Here's a picture of my monster.
