I believe the TH350 pump is like the TH400, where two of the pump-to-case bolt holes are tapped for the slide hammer. I believe they are the two at 3:00 and 9:00. The Kent Moore tools for this are a pair of small slide hammers so you can pull both sides at once, but I've had no problems pulling the pump on a TH400 by using a single slide hammer and going back and forth between the two holes. I fabricated an adapter for my slide hammer by welding two bolts head-to-head. One end screws into the slide hammer and the other threads into the pump holes.
you can also pry up with screwdrivers inside the case if the oil pan is off.If you simply screw 3/8 bolts thru the pump enough it will push the pump up alittle.If you replace the seal you should replace the bushing too.the converter snout should look good and not scoured.When you split the pump halves you must realign the halves on assembly.18Ft lbs on torques if i remember
Lube the bushing and pre fit it on the converter lube the seal make sure the slots on the converter line up and seat all the way in the pump
if your going to buy a new seal and converter then you for sure want to put a new pump/converter bushing in also thats why u would split the pump halves apart
if your going thru all the work do it right and get all the seals and gaskets for the pump