I've had this 36" single-stage snowthrower since 2004 or 2005. It has been on a 1450 and 1512 I used to have and the 782 I currently have. Shown is my Dad using it to clear a massive 20" snowfall in early 2011.
It worked great on the 1450 and 1512 but ate belts quickly once I put it on the 782. I eventually determined that this was due to belt misalignment. Beginning on the 82 series tractors, the engines are tilted up at the front at about 3 degrees. This was not done in any previous series. Consequently, the belt would rub the back edge of the thrower pulley and destroy the belt in 20 minutes or so. I modified the snowthrower slightly to angle the gearbox to line up with the engine, and now it works perfectly.
I bought a new U-joint from McMaster-Carr to use in place of the OEM stamped steel U-joint. This is a huge improvement.
Everybody complains about how hard these are to attach because they don't know this trick. Remove the right upper link and place it as shown, with the stub bolt in the lower arm in the slot in the upper arm. You can now basically roll the tractor into the thrower. This is much easier than any other alternative method of attaching it.
The above picture shows what I did to line up the gearbox input shaft and the engine. I removed the original spacers for the sliding gearbox plate, and made new longer ones on the lathe. I then ground washers that were thick by the center hole and thin by the outer edge, and put them between the sliding plate and QA mount with the tapered side facing the sliding plate on the lower pair of bolts, and placed them on the 'nut' side of the upper bolts, as shown in the picture. I spent a lot of time adjusting the washer thickness until I could tighten the bolts fully yet have the plate move without binding. There is minimal slop in it now. You can see the that the two plates are no longer parallel. This is what is necessary for proper belt alignment when using a QA-36A or QA-42A on any 82 series or newer tractor.
The consequence of my modification is that the adjuster bolt no longer fits into the hole in the gearbox plate, so I made a tab with a hole in it where the adjuster bolt wanted to be.
This is one of the very few times I'd make an un-reversible mod to an original attachment; I drilled a hole for a 1/4" stop bolt so that the belt tensioner handle can't back off. This will also go a long way towards extending belt life, as they do tend to vibrate loose, particularly on QL tractors with big engines.
What this REALLY needs is a spring loaded belt tensioner on the slack side of the belt. That would wrap the belt further around the rather small pulleys, making it less likely to slip, and also let the belt self-tension. When the belt gets hot, it expands and the tension decreases unless there is a spring-loaded tensioner. Someday I'll get around to performing that modification.