I have thought about this my self. And if you are talking about rs 275 i think the trouble will be weight! At only 50 lbs less than the 400 inch motors with same jet will be hard to keep up. But yes i think a 363 with a 82 jet will run 50s. But at that weight it would have to be a perfect run.
I built and tuned a 364" sbf based on a 8.7 deck with a single stage fogger weighing 3050#... It was a NMRA EFI RENEGADE car with brodix track 1 heads and a .545 lift hydraulic roller. With a c-4 and a .038 jet it ran a best of 5.33 at 133 mph... Around 700 hp on muscle... You can do it with a 363 done right with a small jet but it's gonna be alot easier with the 418