With the power this 454 is capable of; 100+ is not a challenge.
Based on my own experience with a 6000 pound pickup pulling a 6000 pound trailer, powered by a 454 backed by a TH 400 I'd believe 100+ is possible with a modified motor, though either that motor will be screaming, or your rear gears will be less than ideal for pulling.
I'm not sure mine would have done 100. Using an online calculater and tire size from memory, mine would have been turning 4400 at 100. This was with a stock TBI 454 and 4.11 gears and 265/75-16s. I never drove it that fast even empty.
I ran mine loaded across some states with 75 mph speed limits and probably ran 80 plus at times. Fuel consumption was significant and I would agree a focus on good brakes is absolutely necessary.
