In the 60s, and 70s, TH350s were as popular as the pathetic P/G. Both got dumped in a serious racer, in favor of a Muncie, or a TH400. A stock 350 behind a "drag racing" motor always lost the intermediate sprag, in short time. If you were stuck with an automatic car, and not a Muncie, (which wasn't a whole lot stronger) then the tranny of choice was a TH400. In stock form, the TH400 was the strongest and most reliable automatic out of Detroit. Even over the C-6, and 727s. Because a TH400 has a center support carrier, that no-one else has.
Supposedly the new 4L-60s/80s (?) are a TH400 with an OD, and maybe they'ld be a good replacement for an automatic car, but I can't say, cause I've never looked at them. But unfortunately, they only come with a chevy bell. I "do" have a 93 2500 military issue stakebed truck, with a 6.2 diesel, and a 4L-80, and it shifts like a bear. Not an automatic fan, but this tranny does feel better than most. If you have-ta build an automatic behind a BOP, I guess the 2004r can be built to handle.
But like soupman mentioned, with todays aftermarket components available, you can build anything to survive. And because class racing has all but disappeared, and the talent of drag racing has changed from building and driving a car to beat a similar one, now comes down to who can run closer to their dial-in. Which has now put the nasty P/G to the forefront. It only shifts twice, and you don't need a clutch. Makes your chances of winning that much better. So you can run a Hemi Cuda, against a 4 cylinder Pinto, and not know the out come. Sounds exciting, don't it?
As for your situation, lesser power has always been cheaper, and more reliable. It's just how much fun do you wanna have? It's all relevant.
(The yawning emoji isn't in reference to "your" situation, but drag racing with a P/G. )