Thrust Block with 489 Sure Grip

You are a tad confused. It's not predicated on the housing, it's the suregrip unit itself.

Clutch type suregrip has the thrust buttons. The buttons are easily removed.

Cone type suregrip has a thrust block. In order to remove the thrust block the suregrip unit itself needs to be disassembled.

IF you have the newer Greens then I think the buttons/block can stay. If they are the older ones it needs to come out.

OR as mentioned if the splines on the axle ends are long enough you can just remove a little bit of the axle end.

Yes thank you. I corrected myself on the matter above back in post #12.

On a related note though, it doesnt seem like there is a whole lot holding these Green bearings firm in their place. I feel like they'll want to spin inside the housing. What do you know about that?