Picture of Flexplate and torque converter here:
http://www.z32photoguide.com/images/tq_cnvrtr_loc.jpg
Picture of one of the FOUR bolts that hold the torque converter to the Flexplate here:
http://s3.amazonaws.com/f01.justanswer.com/pennfostergrad/2013-03-04_233851_flexplate_gap.jpg
Before unbolting the transmission bellhousing from the engine you need to remove the FOUR bolts:
https://i.ytimg.com/vi/iYLaYreWZ4c/maxresdefault.jpg
By rotating the engine 90degrees each time you remove one bolt.
Once all FOUR are removed you can then put a screwdriver in between Flexplate and torque converter and push them apart, it will only move 1/4" or so back towards transmission
By removing the torque converter with the engine you may have broken the Front Pump inside the transmission, no way to tell until it is back together and transmission either works or it doesn't.
Most likely trans will be OK, but putting it back together is when biggest danger of broken pump can occur
..........FOR SURE, remove torque converter now and BEFORE putting engine back in, install the torque converter on the transmission FIRST.
Torque converter MUST BE aligned with Front Pump Drive and input shaft drive, which is why you wanted to leave it in place and not pull it out with the engine.
Short Video here on seating the torque converter into the transmission:
www.youtube.com/watch?v=g7klzEV0kng
It should slide in 2 or 3 times while you rotate it
And it should sit INSIDE the bellhousing, nothing sticking out
When you bolt engine back to transmission torque converter should NOT press against Flexplate, once engine/trans bolts are tight torque converter should spin so you can align it with flexplate holes and install the FOUR bolts
Install bolts finger tight but not wrench tight until all FOUR are in place, then you can tighten all FOUR
This is a VERY VERY BIG deal
Most here will have a "first automatic transmission" story, I do

I broke the front pump on my first automatic install, an expensive lesson, complete trans rebuild was needed to repair it