V8 FIERO project

1988 Pontiac Fiero with a 4.6L Cadillac Northstar V8 swap


  • This project is a 1988 Pontiac Fiero that has the engine, transmission and electronics from a 1996 Cadillac Seville swapped over. Everything is made to look stock like it came from the factory.
  • The original 2.5L Inline-4 in the Fiero came with 92 horsepower. The 4.6L V8 now installed has 300 horsepower. It also includes the 4T80E 4-speed automatic transmission.
  • All aluminum V8 doesn't weigh much more than the cast iron 4-cylinder it came with. Total weight is 2600 lbs.
  • Front axle is stock but drilled to accept the 5 bolt wheels from the Cadillac. Rear axles are from the Cadillac. Brakes are upgraded parts from a C4 Corvette.
  • The Fiero is a mid-engine car with the engine seated behind the driver. The drivetrain layout is transverse, so virtually any FWD drivetrain that fits could be adapted to the vehicle.

32-Valve v8

northstar power

The 32-valve 4.6L V8 Northstar engine generates 300 HP @ 6000 RPM and 295 lb/ft torque at 4400 RPM. This the L37 high-output version - a high-revving DOHC engine with a 7000 RPM redline. PCM is a factory modded tune with VATS disabled. All modules from the donor car are installed. OBD2 port works and scans properly. 91 octane fuel required. Custom Magnaflow high-flow exhaust installed. Best 0-60mph time on pump gas is 5.1 seconds. Pounds-per-horsepower ratio is 8.66, which would put it in the same class as a 2017 Chevy Camaro SS, which has a ratio of 8.61.


With no aftermarket tuning options based in the US, v8fiero.com is working on a custom open-source PCM that will plug and play into the factory harness to control the Northstar 4.6L V8 engine. The Northstar PCM from 96-99 cars has two separate units inside the PCM - one controls the transmission and the other controls the engine. This open-source solution will control just the engine side. A separate controller from ETransControl (http://www.e-transcontrol.com/gm-transmission/) will run the 4T80.