Have a 68 GTO convertible,that i originally thought was Pontiac based on the color.I found numbers stamped on the ,passenger side at about 10 o'clock left of the water pump.386602 with YN,below the numbers.The closest i could decode was up to the first 6 on an Olds motor..Anybody have a clue as to the year?..By the firing order its a 350 thanx

Have a 68 GTO convertible,that i originally thought was Pontiac based on the color.I found numbers stamped on the ,passenger side at about 10 o'clock left of the water pump.386602 with YN,below the numbers.The closest i could decode was up to the first 6 on an Olds motor..Anybody have a clue as to the year?..By the firing order its a 350 thanx

The YN stamp indicates a 1968 Pontiac 265 HP 350 which would be a 2bbl carb / small valve. The numbers are a partial VIN number from the original car.

Pontiac engines have an "air gap" intake whereas the intake runners and water crossover are separate from the top of the block. Also the CID is cast on the driver side of block on the "V" between the front of block and motor mount. "350" in this case.

The Olds engines have the oil filler tube in front of the engine block.

DanC