Torque converter affecting idle question

If the Vcan was making it pop, Ima suspecting rotor phasing is the issue. It would explain all your woes.There is no way that at cruising, say 2200 rpm,it should be popping, and most especially not out the exhaust. Even if you had an exceptionally fast curve, and an exceptionally generous can, that would still still be about 45-48** total cruise timing. I have run my combo deep into the 50*s at 2200, with nothing but a thank-you from my 360S.
Popping out the exhaust is usually a rich mixture continuing to burn in the header or a little further down. It has to have fresh air for this to happen, which usually points to a leaky gasket (or rust-holes), at the flange or the collector. If you fix the holes/leakage, and lean it out a tad, you will be able to reconnect the Vcan, and enjoy the benefits that brings.
The TTIs have pretty good header-flanges, but they only have a 3-bolt collector. Also, if they are over about 5 years old, and not ceramic, they are subject to rusting in the area where the pipes enter the collector,up top,between the pipes. I've had to repair mine there several times in 15 years, and they need it again. Moisture collects there.

A simple test for rotor phasing is to rev the engine up,(N/P) to a little higher than where the mechanical timing is all in, and then begin adding the Vcan timing. The engine should respond to that, by building more rpm, until it's too much. But I doubt you can reach that point, because typically the all-in rpm is 3200 +/- 400, and will be about 34*+/-2. The Vcan will typically bring in 12 to 16 more, for a total of 34 + 14 = 48 +/-4. That's 44* to 52*. Easy-peasy for the SBM. But if it begins to pop or missfire or actually loose rpm, then you need to rephase the rotor.

If I'm wrong, it'll cost you a bit of time to prove it, and nothing else.
If I'm right, then after the rotor is rephased or the exhaust is sealed up, or both, then you can begin to zero in on the timing that the engine is wanting,perhaps craving.