I'm nobody here, but the rating of a torque converter is contiginent to the torque applied. Meaning your big cube motor is going to stall more than a MP484 cam'd low comp. 440, as an example.

Tall tires and tall gearing will make matters worse given the rolling resistance. Excessive heat losses is generally the byproduct unless you have a really close tolerance built converter and a very big cooler too. Is your driving more rural hwy or innercity suburbs??? If rural, you may get away with it but it may not actually "hook-up" or couple fully at hwy speed (hence, more heat losses)

I'd rather have a little too much converter and be well into the torqueband than dogging the motor down with one that is too tight.