It should actually be a 4.5L. I have a 1990 Sedan DeVille with the 4.5L in it, which was actually the prototype for the Northstar engine. There was a 4.9L in '91, which is a stroked 4.5, but is actually slower off the line than the '90.
Anyway, I'm not surprised. That Cadillac engine is one of the fastest accelerating engines I've ever seen. It is
very fast accelerating up to about 50-55 mph, then starts leveling out, but still has plenty of power even past that. I've raced several people in trucks; raced my uncles '70 C10, someone in a Ford Ranger off of a stop sign, a couple of idiots in rice burners, an 80's Ford Thunderbird, a late '90's Mustang, etc. and pretty much smoked them all. Once I get a new computer chip for it from superchips.com, I figure it will be even faster.
By the way, how did he know he was going 97 mph when all Cadillac speedometers only go up to 85?
(ok, my memory is a little faulty; maybe the Sevilles had a different gauge configuration)