Rick, you likely have the factory short shifter installed. Check here:
Seine Systems > An Overview of 915 Shift Housings
Sherwood's site (he also produces the Seine Systems Gate Shifter Kit offered by our host) provides some measurements to verify whether your shift lever is indeed the Factory Short Shift lever. The fork in your photo (rectangular box) is arched as the FSS would be; a 'regular' (non-FSS) for an '84 would be a one-piece fork, totally rectangular.
The FSS works in the regular housing by: a) moving the pivot point upward (toward the knob); that's why the FSS yoke is arched -- to move the pivot point higher; and b) by providing a shift lever that's slightly longer between the pivot point and the ball end. That way the FSS 'reaches down' as far as a non-FSS, but because of the revised fulcrum/pivot point translates to shorter (though not necessarily faster or easier) shifting.
You want to be especially careful reassembling your shifter. Since you have two forks (one FSS, one not), you need to make sure you use the proper fork for the lever you have. If you use the FSS fork (higher pivot point) with a 'regular' '84 shift lever, the overall length will be too short and the shift lever ball end may not seat fully into the bushing and holder. If you use the 'regular' fork with an FSS shift lever the lever ball end will sit too low, and as you reassemble the shifter it'll be too long overall. You very well could be in a situation where the shifter rod bracket (you know, the one with the PITA hex bolt) can't sit flush with the bottom of the shifter housing and -- in an attempt to tighten those two hex bolts -- all kinds of bad things can happen, including binding the shift linkage or stripping the female threads in the shift rod bracket. My suggestion is that you take the shifter off again, measure everything just to make sure, and blueprint the shifter. Poke around the Seine Systems site; you'll find lots of useful info there including how to 'blueprint' your shifter.
And, as Wayne pointed out, the shift lever should move right of the tab when shifting into 5th, so the tabs (one on the plate, one on the shift lever) hold tension against the shifter springs -- not the trans itself (you want to avoid the side load). Proper adjustment of the coupler under the access panel between and behind the front seats is a must, and will likely take a few tries and a little finessing to get just right. But when you do, it makes a world of difference between a PITA experience and fine-shifting 915.
Good luck,
Dale