You can make that tunnel ram work. It is not ideal for street use but can be made to run.
Your power band should start ~3200, I would think a stall in the 3000 range would be a minimum. 3.73 gears would also be minimum.
You said you upgraded to a larger acc pump, right? Did you change the acc cam as well? If you didn't you really haven't changed anything. You will have to find what works for your combo as far as with acc cams. Your bog is cause by a lean condition (as described above). You may need to change your squirters as well. It would take a lot of typing to explain the whole tuning process. Does the suggestions above make sense to you? I don't know how much carb experience you have. I don't want to get to carried away.
With your stall you need to understand, that those long runners (tunnel ram) make very little torque down low, this means a converter that would stall at 2500 behind a non tunnel rammed car may stall only at 1800 behind the tunnel ram. Add a tranny cooler if you don't already have one and increase the stall to at least 3000-3200 (if you are buying off the shelf stalls).
You have a relatively small engine so it will be a little more crucial to get tings just right if you want it to be fun to drive. With a larger engine and a tunnel ram it is easier/less finicky, more forgiving. They make more torque so it covers up some of the downfalls of the tunnel ram.
One last thing, I think a solid flat cam would have been a better choice for this application. To make any power you are going to have to spin that 350 and the hyd roller is not the best type of cam for that. Your effective power-band will be from 3500-6200 if everything is tuned perfect. With a solid flat tappet you could stretch that power-band out to 6700 (maybe more). Tunnel rams are made for higher RPM operation.
Hang in there this is part of hot rodding, make it work.
OH, one very important question, what kind of compression are you running?
Let us know how it goes.