Factual error: While handling the ignition coil cable to the distributor cap, Joe Pesci tells De Niro that the timing chain needs adjustment in his truck. A truck of that year with an inline Chevy motor would not have a timing chain at all, instead this truck would be equipped with a direct drive timing gear. Even if it had a timing chain, it would be behind the water pump and a cover. It would have been a several hour job to replace, not possible to adjust it.
Factual error: In the movie it says Allen Dorfman was shot in 1979 - he was actually shot in 1983. (00:56:25)
Factual error: When Frank drives up the street looking for the "Hoffa hit house" there is a white 2001 Mercedes van sitting at the driveway beside one of the houses. (02:37:33)
Factual error: When Frank watches TV the news anchor says that Crazy Joe was killed at age 47 - he was 43. (01:47:25)
Factual error: The twin engine Cessna 421C airplane which Frank travels in has modern avionics upgrade not available at the time. Tail number N212RV wasn't issued an air worthiness certificate until June 1979.
Factual error: When the Machus Red Fox is shown, it is depicted in the middle of a country road, with mountains in the background. The actual Machus Red Fox at the time was on a busy street behind a strip mall on Telegraph road near 15 mile. Also, big hills that are shown in the movie are non-existent in Michigan.
Factual error: In the opening scene when De Niro is mapping out his route from Pennsylvania to Detroit, the map shows interstate 275 which wasn't even built at that point.
Factual error: During the trip's second stop for smoking, the overhead wiring has an optic fiber box joint visible, which doesn't fit for that year. (00:21:18)
Factual error: When plotting the trip to Detroit, it show Frank drawing his route as I 80 merging onto 75N in Toledo toward Detroit. Toledo is approximately 60 miles south of Detroit. When actually driving, they stop at a HoJo's and pass a road sign that says Columbus 64, Dayton 86 and Detroit 212 on I 75.That puts them going north on I 75 between Cincinnati and Dayton. That would have put them 160 miles south of I-80.
Factual error: Despite the great effort (and expense) to recreate the 1950s through 1970s with vintage cars, SOHIO gas stations and a HoJos motel, none of the houses in any of the street shots show TV antennas on the roofs or chimneys. It's highly unlikely that every home on a given street used "rabbit ears." Cable didn't make inroads until the late 70s at best.
Factual error: Multiple scenes show cars with Pennsylvania license plates on the front bumper. Pennsylvania did away with the front license plate in 1957.
Factual error: There is celebration in Little Italy. A police officer is trying to stop a shooter, and his uniform has a 12 on the collar, signifying supposedly the 12th Precinct of the NYPD. There's no 12th precinct in the NYPD. The real 12th precinct was abolished in 1916, and the building was used as a police storehouse after that. (01:38:35)
Factual error: Frank boards a Cessna 421C twin-engine airplane. The pilot "starts" the engines, but only one is heard. You would have to go through startup procedures for two engines. Worse, it starts up instantly, but the mixture controls for both engines are at idle-cutoff, and both throttles are at full power. Not the procedure you use to start an engine, let alone two. (02:34:50)
Factual error: When Frank takes Peggy to grocery store to beat that guy up, it takes place in Philly's Italian Market in south Philly. Meanwhile the street sign outside the store says Allegheny Ave, which is actually opposite side of town in north Philly.
Factual error: When Frank plots the road trip he says they'll start off going up 476 to Pittston. In 1975, that road was called the Northeast Extension of the Pennsylvania turnpike. No one called it 476 until much later.
Factual error: When they pull up to the house in the red Marquis to kill Hoffa, the front license plate has Michigan plates from 1973. Hoffa disappeared in 1975.