1987 B230f Main Bearing Confusion

[Bluebrick91]

I am in the process of rebuilding a 87' B230f and have stumbled upon something strange. I had always been told the middle of 1988 was when the large 2.4ish inch main bearings were introduced and the rear thrust bearings but this engine is a 87' and has the same 2.43ish inch bearings.

This is a rear thrust bearing post 1988 crankshaft I presume that came from the 1987 engine that was pulled from a JY 240 by the guy I had bought it from. The milage and year of the car it came from is unknown.

These are the years of the engine and head which are both 1987 year coded.

I had also made a spreadsheet of all the measurements taken from the engine to double check if I was right about the sizes of the main journals. I am just curious if this means the engine is basically as strong as a post 1990's engine if I swap thick rods in and I wanted to put this weird engine out there to see if anyone else has experienced this.

 

[dl242gt]

Well a 12/87 engine date would mean 88 model year. So it seems consistent with the change over time. Yes, it would mean it's the same as say a 1991 block.

 

[OVERDRIVE]

"Middle of 1988" would mean model year. 12/87 puts that in the middle of the '88 model year. From everything I've heard this checks out. My 3/90 240 has a 12/89 motor, so in reality this motor likely came from a later '88.