I know for a fact the spicer part # IS 5-3147X. This is a Mechanics STYLE, 3R SIZE u-joint based on the cap retention style and dimension.
The no-grease u-joint is actually stronger because it has not been drilled for the grease to flow to the trunions and bearings. The spicer # for that one is 5-3011X. These need to be packed with grease as they are installed.
This brings up a point to be made for those that install their own joints. If you install a greaseable joint backwards it will of course fit, but when you torque the drivetrain, it will pull at the grease fitting location and is capable of pulling it a part.
If you are lubricating a greaseable joint, pump it untill grease purges from all corners. Except for a very few, the seals are made to purge and if you aren't getting grease out of one, it may not be getting grease.