AC serial number, please help!!!

I purchased an Allis Chalmers WD and can not figure out it's true year. The serial number on the left brake housing does not match up with WD years, it falls into WD-45 years.

The starting numbers of my serial number are 164*** All the information I find show my numbers as a 1954 WD-45. But on my motor (spark plug side) it has a cover plate with 6 large bolts, which from my understanding is non-existent on the WD-45, thus pointing my tractor to be a true WD.

What really confuses me is the last year the WD was produced in 1953 it was issued the starting serial number 131***. Then also in 1953 production started on the WD-45 and was issued the starting number 146***, and then in 1954 the WD-45 starts production with 160*** which is where my serial number falls (164***).

If anyone can shed light on this and help me figure out the year of my tractor it would be greatly appreicated.
Thanks.

Thanks Lonn. I definitely wondered that. My serial number says WD in the beginning of it, does the WD-45's serial numbers also start with WD?

Mack, isn't the rear housing all one piece, the whole entire axle? I'm asking because I am new to Allis Chalmers. But if it is all one piece it sure seems like a lot of work to swap that, yet not impossible I'm guessing.

Thank you all so much. I realize so much can change from one tractor to another in 60 plus years, farmers did what they had to do to keep them running. So for my records I think I will consider it an Allis Chalmers with a WD-45 frame and a WD motor. If I clean it up and put new stickers on it one day I will label it as a WD because that's what the motor is. Thanks again everyone!!!

Dmpaul89, I never thought of that. I think you may be on to something because the previous owner told me the motor was rebuilt years ago.
Thanks!!!

Curved. I heard before that late model WD's switched to them and WD-45's had them as standard. Not sure it's true, just what I've heard.

If it has a 45 transmission and 45 engine internals I'd decal as a 45. But in the end you can do as you see fit.

Thanks everyone for your replies, I truly appreciate it. You have all opened my mind to different possibilities that are very helpful.
I tried visiting the guy I bought it from but he wasn't home. I was going to see if he had any information other than what he told me the day I bought it. I know he'll openly tell me what he knows because I've known him for 42 years, but I didn't ask these questions to him originally because I didn't know enough to ask.

The WD and WD45 were never built concurrently. The last production WD was immediately followed by the first production WD45. I'm pretty confident in that.

Rltool, I am 60 miles north of Grand Rapids, close to Fremont. Thanks for the how to on checking engine stroke, I had absolutely no idea how to do it.

As a example, I have a 1950 WD that had the center section of the rear end changed 25 years ago. So the serial number on the casting is from a newer tractor. I would recommend you talk to the previous owner and get as much info as possible. Sounds like you may have a WD45 with WD block.
Carb will be bigger on a 45 than a WD.
Regards,
 Chris

I talked to the guy I bought it from and he confirmed that when he bough the tractor many years ago that he was told it was indeed a 1954 WD-45 frame/body, and a 1953 WD motor. He was told the motor was rebuilt and he just assumed it was rebuilt the same (WD), but now he too wonders if when the motor was rebuilt if it was converted to a WD-45. So I will check the engine stroke and see what I come up with. Thanks everyone, you've all been so helpful to me and I truly appreciate it.