When Abigail gets on the dirt bike, she puts the gun strap over her right shoulder, then in the next shot the gun is across the handle bars.
When Al and Elmo are backing up away from the police shooting at them, the rear deck trim is red. All other times in the film, it is black.
During the fight scene in the bar, the hats for many of the patrons disappear and reappear between shots.
The convertible top on the 1964 Corvette, and all Corvette convertibles from 1953 to 1975, has the folding frame bolted with two large bolts on each side to the pillar just behind the seats. Elmo would not be able to access the bolts without removing the cover side panels and could
not remove the bolts without tools. Unlatching the front of the top at the windshield would cause damage to the top at speed, but the top would never just lift off the car and fall to the ground as shown. This stunt has been used in other movies, notably in Star Trek (2009) and is probably assumed to be real.
Lonigan comments about catching the Corvette with only 4 cylinders. Rather than being a statement on the engine, this is more likely a commentary on how badly the engine is running in that only four of the eight cylinders are firing correctly.
When Abagail jumps over the car with the dirt bike. The reaction of the woman in the passenger seat is delayed.
When Tony asks Abigail is she retrieved the jacket from Elmo. She asks what's so important about the jacket and Tony angrily tells her "the homer is in the jacket!" She responds "now we're right back where we started!" She has no reason to be angry because if she did in fact get the jacket, they would have no way of tracking down the drugs.
Lonigan says to Tony, "You tell your grandchildren about this one friend, Ole Lonigan on 4 cylinders caught a Corvette of a pro". Lonigan's character drove a 1971 Chevrolet Chevelle Malibu, which was never made with a 4 cylinder engine.