403 olds

[78 LS3 TA SE]

Im restoring a 78 y88 Van Nuys CA. built car. I purchased it with a Olds 403 engine in it. The VIN has a Z so it should have a 400 in it. Is it possible there was a mistake or was the engine swaped? Thoughts.
Thank You

[Oldsschool79]

Check for a partial VIN# on the engine block just under the left front cylinder head. The number should be just beneath the exhaust manifold. My 403 had the last digits of the VIN# stamped in the block and it was also a California car.
It does sound like someone swapped the motor.
Hope this helps.

[Maxthe222]

No, impossible. The 403 was a HA/Californian emissions engine, and if your car was originally sold out of a federal state, it would have had the L78 400 Pontiac engine. If you have the buildsheet or PHS, you may even see it was ordered with the pay extra W72 400 Pontiac engine. If you know the car is a Y88, you must have PHS or the buildsheet as you've also stated the car was built at Van Nuys, which did not stamp the cowl tags with "Y88". The PHS will further prove what engine it came with.