Technical Decoding a Stovebolt 235

I drove over to M***. yesterday to look at a 235 inliner that was rebuilt but never installed. The party that had it is a very respectable collector whom we have dealt with on other deals. He had received this engine as a package deal along with a couple of other items. It looked respectable and clean, had great compression so we bought it to replace this nagging engine issue with my friends 53 3600 truck.
The block numbers indicate that it is a 54. Those casting numbers are CON1 H124 making it a August 12th of 54 build. The other serial number is 0964300 F54X.
So it was built in Flint in 54 but i cannot find any reference to the X or the 09 serial number in 1954 specs on line.
Anyone run across this before?

 

should just be a 1/2 ton pickup truck engine? this from the 1954 GM Heritage Information

 

Im no expert on those but the 0964300 should be unit number and F54X is Flint 1954(X)- 3100 Series. I ***ume standard transmission as F54U is HD Clutch and F54M is Automatic.

 

This is the go to page for 57 and prior chevy six cylinder ID https://chevy.oldcarmanualproject.com/models/engine.htm

I'm not seeing an X so we will move over to the GM heritage center vehicle information kits for Chevy
https://www.gm.com/heritage/archive/vehicle-information-kits Click on 54 truck and scroll way down the page https://www.gm.com/content/dam/comp...its/chevrolet-trucks/1954-Chevrolet-Truck.pdf

And Bingo 54 3100 truck engine built in Flint Michigan . If you scroll way down the page it will give you the original factory low down on that engine.

 

Well, that was quick! Thanks guys.