It'll be one side or the other, not "up or down", Looks like your good to go, all you need to do is possition the converter with the hub faceing down (just don't tear it up) use a box or piece of hard foam to support the converter, having the bolt holes faceing up, then lay the flexplate on the converter (weights/lip down), then spin the flexplate untill you can put in 3 bolts (make sure it centers), then you'll see where you need to elongate the one hole, make sure all bolts go in before assemble. If your going to use the existing converter thats in it, make sure it has "no" weights, if it does, you'll need to knock them off. Use the stock H balancer also.
Another issue you "might" have, is putting the starter on, the older 904s/727s had the starter possitioned a bit different then the newer trannys, Check & see if there is a "boss" on the block where the starter will be, this boss should have a hole in it, if so, you'll most likely have to trim off about a 1/4" or more so the starter fits flush & not cocked. I had to do this on my 95 magnum 360, seeing yours is a 99, it may not have it, i didn't realize this problem untill the engine was in place & i was installing the starter :-|, but i was able to sneak my die grinder in there & trim it down thank god.
