Gravely L8

I have a gravely L8 that is supposedly a 1949 model, however it has a vertical spark plug and modern style canister oil filter, but also an oil bath air filter. From what I've come up with, it should be a 5hp engine, but that's supposed to be an angled spark plug. Is there any way to tell what I actually have? I suppose it's easy enough to replace the fuel tank with one off an old model, which could explain why it has a 49 model number.
Any help on figuring out what I actually have is appreciated.
Thanks

The 8 speed gravely came out in the mid 1960's. It had the vertical spark plug 7.6 HP engine. Many of the parts from the 1940's would fit later models.

The Gravely engines used a multi piece crankshaft. When the pieces of the crankshaft got out of alignment, varying degrees of vibration would occur. This vibration caused metal fatigue. One of the first pieces of metal to fail from fatigue was the bracket that attached the gas tank to the rest of the tractor. This is the reason that many gas tanks were replaced over the years.

How would I go about verifying that's what has happened? I assume just knowing the fact that it has the vertical plug, but an early serial number are enough, but is there something else I can look at to know for sure?

I'm a geezer and my memory isn't as clear as it used to be (and never was???). I got interested in the Gravely walk behind tractors about 30 years ago, but my interest migrated to the later Kohler engine models as I got older, the local Gravely dealers went out of business, and Gravely engine parts got more scarce and expensive.

One on the best sources of information would be in the various manuals. You can find a lot of these available for free download at various sites such as:

https://manuals.gtcoa.com/docs/index.html

So many parts could be interchanged between various models made from the late 1930's through the early 1970's makes it difficult or impossible to determine exactly what you may have. You might have what was once a 1949 model that has been upgraded with a 1960's or 1970's 8 speed transmission. I vaguely recall that the oil bath air cleaners were only used in the early 1950's. Early models didn't have an oil pressure gauge. Your straight up spark plug indicates only that the engine head is from a later model 7.6 hp engine. Upgrading heads in an attempt to gain horsepower was fairly common.

Good luck with your quest!!!

Interesting. Thanks for the information. I'll be sure to check out the manuals

1949 was a long time ago, correct 1949 parts got scarce and people did what they had to to keep their machines running. If the correct part wasn't available or the new part was cheaper, fit, worked and maybe even increased horsepower you can kind of figure out what happened. I know with Cushman products when they changed or improved things on the trucksters or turf trucksters if you had an older unit and ordered a replacement part through a Cushman Dealer you'd often get a service upgrade kit instead of the part so you got the new and improved part and everything you needed to make it work. Once I ordered a mechanical fuel pump for a Turf Truckster, they sent me an electrical fuel pump, a bracket, a wiring harness and a bag full of fittings.