Gears & Axles - ujoint for moser 1350 yoke?

I have the spicer 2-4-573 that is supposed to fit it but it doesn't? Anyone know the correct one or another brand that fits it correctly. I am using the stock one for now and its not very strong. Thanks.

I used Precision Bearings part #447 for my Moser 1350 yoke and stock driveshaft, costs about $28.