I told them which engine it was. They still gave me the wrong starter, and said "yep, it'll fit that engine".My guess would be that in 79, your car could have come with a 301 Pontiac with a 2v carburetor or a Chevy 305 with a 4v carburetor. They're both 5 liter engines. The parts store should have asked you the vin. That would have told them what engine the car came with.