I am in the process of tearing down a nice side shift transmission. It appears the box has been opened up at least once. It needs the usual attention to dogteeth and first and second gear syncros. What I question is the pinion and input shaft bearings in the intermediate plate can be rotated by hand in their bores. How much movement is acceptable. I have the retaining plate removed and with finger pressure, cannot push the bearings out of their bores. So in summary with the bearing retainer seated or off, I can rotate the bearing with light/moderate finger pressure. Normal?

Take a look at the bearing recesses in the intermediate plate and you will see the bearings have worn into the retaining plate. The plate is made to provide 0.06 to 0.08mm interference fit on the bearings. You need to get the plate reworked to provide the interference fit or get a replacement plate.
That said, if the bearings are not to loose,you can reinstall the bearings with sealer and it should be OK.

Great info!

I'll remove the bearings from the plate and look for wear. My guess is the magnesium would likely wear before the steel retainer? Under load though are the bearings being pushed against the retainer or the plate? Even with the interference fit, should there be some amount of movement? What type of sealer are you referring to? I read one thread where sealant was used and was non existent when the box was taken down a short time later.

Technically the plate is shot and either needs to be replaced or machines and rebushed. However, some have put high temp locktite on the bore, or have staked the metal surrounding the bores as a "fix". Just as long as you understand that this may fail.

I pressed the bearings from their bores this evening and found that apart from some discoloration from dirty fluid, the seats look good. There is a barely perceivable ridge in one area that you can feel with a fingernail. I'm inclined to reuse the plate and remove a small amount of material from the bearing retainer.

OR... should I go billet plate?

Intermediate plate bearings cannot be allowed to move. If they start rotating in the plate they only get worse and eventually bad things happen.
Here are some thoughts on what happens inside a transmission.
The two shafts are supported by a roller bearing and a ball bearing and are subject to 3 forces.
Axial forces are developed by the gear contact angle and the pinion/ring gear contact. The mainshaft is pushed into the intermediate plate by gear contact in normal driving and pulled away on overrun.
The pinion shaft gear forces are opposite but there is an additional reaction force from pinion gear contact with the ring gear that pushes the pinion shaft toward the intermediate plate. This axial force is opposite to the gear angle force and results in a net reduction in the load on the pinion shaft ball bearing. Flipping gear pairs reverses the gear angle force which means they are added to the pinion force instead of bearing subtracted. Bearing load is increased but since the pinion bearing is well dimensioned, doesn't seem to be a big problem.
The bearings are also subject to radial forces because the shafts are pushed apart when power is transferred between 2 gears. The radial forces are distributed between the shaft ball bearing and roller bearing depending on the distances from the point of load. The upper gears are located on the roller bearing end of the shafts which is good beause most of the time, power is transmitted in 5th gear.
The 3rd force is a turning force internal to the bearing when the inner race tries to turn the outer race that is fixed in the housing. It is a weak force but is enough to spin the outer race if it is not properly fixed.

A little more Porsche trivia.
The first picture is a 356 transmission intermediate plate from about 1962. The bearings are held a retainer that completely covers the bearings. The original version of the retaining plate from 1958 was similar to the 901/914 plate in that the mainshaft bearing was held by a fork that did not enclose the bearing. Porsche saw a need to strengthen the bearing support for the late 356 transmissions but forgot this lesson when they designed the 901.
The 901 1965-69 transmission was aluminum and didn't have problems with loose intermediate plate bearings. 1st gear syncho would wear out and the mainshaft ball bearing would sometimes fail at less than 100,000KM.
In the middle of the 1969 model year, Porsche introduced the mag case transmission in the 911 parallel to the 914. Most of the bearings and gears from the earlier aluminum case were reused in the later type.
Two pictures show typical wear on a 914 intermediate plate. If you can feel a ridge with your finger nail in the bearing bore or the bearing flange seat, it is not reusable.
The next pictures show typical wear on a retaining plate and a reworked plate.Click to view attachment Click to view attachmentClick to view attachmentClick to view attachment[attachmentid=511
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Incredible write up and detail. I can clearly see how the complete retaining ring would better restrich bearing movement. It sounds like I'm either going to look for a replacement oem plate or purchase a billet.

I love pics. They help so much. I need to get more stock photos of what I have on my bench when I get things that are messed up....I am usually to greasy to operate a camera, and in the zone so dont stop.