Hi Eugene,
Before I get to the reason for my post, I'd like to say that I have thoroughly enjoyed your recent posts and videos. I would imagine that Speed Queen is not as keen on some of them, but I find them very informative, well produced, and incredibly enjoyable to watch. Thank you for making them available to us!!
I have an affinity for belt drives like you do your KA Direct Drive, and have been using them my entire life. No new/modern machines here - The newest washer I have is a 1993 KM 70 series DD which I got new, but it has only 2 years or so of single-person use on it. The rest of my machines are an assortment of Belt Drives, 1960s to late 1986. I rebuilt and sold 50+ of these black panel machines in the 1990s when buyers seemed to be waiting in line for them.
I have three machines installed and ready to use at my house at all times. Currently a 1976 KM 60 standard tub, a 1977 KM 70 almost identical to yours, and a 1980 KM 80. The '77 has been installed this time for more than a year. It has a Penta-Swirl agitator like yours. I thought I would make a few comments about the rebuild, and also about using this machine:
First, these were the largest capacity belt-drives made. They hold a max of 26 gallons of water and were made 1967-1981. The tubs in these are so wide in diameter that the cabinets have rounded cut outs on the inside rim to allow for the wide tubs to be fitted into the cabinet. When we try to reinstall a tub with the tub mounted filter and air dome still installed, and a gearcase in place, it can be awkward indeed to get the tub in place without knocking the air dome. I usually take the air dome off. It often needs to be cleaned of debris and a clean sealing surface created to assure a no leak install, but only a time or two have they caused me much trouble after that.
The drain grommet on the other hand is a different story. This grommet (WP called it an outlet hose) is very different than the smaller grommet used in standard tub models, and in later 22-gallon large capacity machines. On the smaller grommet, they can usually be re-used after removing the outer tub, but original large grommets in my experience have been troublesome to successfully re-use. The sealing grooves collapse from years of pressure under the tub, and simply do not re-seal easily. I had enough trouble with these that I always replaced to drain grommet regardless of leak or not just to avoid negotiating with the machine and a fickle old grommet. New ones of these are still out there, but unfortunately you would have to pull the outer tub again...
As to using the Penta-Swirl --- it takes getting used to, and has its limitations. And this is coming from a belt-drive regular user. For someone more familiar with DDs and late model machines, this agitator may seem very lethargic. I had no exposure to this agitator as a user until I refurbished my '77 in 2009. The agitator does an exquisite job on medium to med-high loads, and is gentile but effective, but once the water level is above the first or second row from the top on tub holes, heavy or large loads are slow to turn over. In fact, when I run my machine full, I add 2-4 minutes of wash time and often double the rinse time to get one or two roll-overs.
If you do some agitator tests with this machine, definitely try a DA. You will see how much more effective the DA is. I would say it changes the personality of the whole machine. The Penta-Vane is better on full loads, but a bit rough on smaller ones to the point that I cut back on wash time when using it.
WP / Kenmore worked for nearly ten years to get a great overall agitator for this big capacity set-up. The original two Bakelite agitators of the 1960s and the big Roto-swirl that replaced the KM agitator seemed to put too much drag on the gearcases, and the two Pentas improved on that, but still had their issues. What you have in your hands is an example of why KM made the advancements they did for 1976 with the DA, and why these were so incredibly successful.
With the DA, extended or reduced wash times are not necessary, even large or heavy loads roll over many times. I think you might enjoy experimenting with different agitators, but since these are pieces of appliance history, the Penta-Swirl is fun to use occasionally. I don't use detergent pods very often, but when I do, full loads get two with that much water involved.
I hope you get your pesky leak fixed and am sorry you are getting indoctrinated on the joys of working on belt-drives --- you can probably see why DDs were designed as they were.
Good luck!
Gordon