What stall converter do I need?

I'm surprised the car ran at all with that combo. I have a 340 Roadrunner with a very similar build that had the old Mopar Purpel shaft car in and as soon as I put it into drive it would die. Changed the cam for a 268 and a 2,000 convertor and all was good.
PTC do a good priced entry level convertor 11" at around $280 which is bult to order one they know your build details
Probably next on my list as I could use a little more stall.