I measured my pan, just to be sure the math works. I do have a 12 x 4 x 10.5 inch sump/kick out on this pan. That confirms it is a 15-680s pan. Mine does have the scraper as seen in the pictures but does not have the windage tray.
12 x 4 x 10.5 inches translates to about 8.7 quarts. Subtract internal edge of the sump instead of the outside, plus volume taken up by the pickup and
oil baffles, I think we are somewhere in the 8.3-8.5 quart range to fill the sump.
Again, the crank stroke is 4 inches, so the throw is 2. The journals are 2.3 (ish), then add a little since the counter weights are a bit longer. I’m guessing the max radius of the crank is around 3.5 inches. Since the pan is 8 inches tall, 4 inches from the block rail (and crank centerline) to the sump, filling the pan to the top of the sump (4 inch) leaves about 1/2 inch to the crank.
I’m going to use 8.5 qts as a max fill. Since I have 6 qts in there now, I’ll add 1.5 more qts and mark the dipstick “fill” mark - indicating a quart low. Then add another quart (totalling 8.5 qts) and mark a “full” mark on the dipstick.
Thoughts? I’ll still call Canton to get their input, but unless someone here has any “that’s the dumbest thing I’ve ever heard” comments, I’ll proceed with this plan.