I’ll suggest if you claim to be adept at Cummins conversions and whatever else you said, and are asking the question, then you already know the answer. And if you don’t, then the answer is, no, you need more/newer truck.
There are so many more things in the equation than just the power train. Namely, it’s a 25 year old truck.
Again if you don’t understand, then put the diesel conversion money towards a newer/ more capable truck.
PS I think gmt 400s are some of the best tucks made, so my statement isn’t about any inherent flaws in the design of the truck.