Well, well, well. This question comes up from time to time and what we have here is a deep pond full of murky water plus several confused alligators. There is a federal law which says "oh you can't do this no matter what." Specifically:
A person may not–
(1)advertise for sale, sell, use, install, or have installed, a device that makes an odometer of a motor vehicle register a mileage different from the mileage the vehicle was driven, as registered by the odometer within the designed tolerance of the manufacturer of the odometer;
(2)disconnect, reset, alter, or have disconnected, reset, or altered, an odometer of a motor vehicle intending to change the mileage registered by the odometer;
(3)with intent to defraud, operate a motor vehicle on a street, road, or highway if the person knows that the odometer of the vehicle is disconnected or not operating; or
(4)conspire to violate this section or section 32704 or 32705 of this title.
(Pub. L. 103—272, § 1(e), July 5, 1994, 108 Stat. 1049; Pub. L. 103—429, § 6(33), Oct. 31, 1994, 108 Stat. 4380.)
And then that part of the law you just read is followed by what I call the "tag on the left door and get out of jail free section" which says:
(a)Adjusting Mileage.–A person may service, repair, or replace an odometer of a motor vehicle if the mileage registered by the odometer remains the same as before the service, repair, or replacement. If the mileage cannot remain the same–
(1)the person shall adjust the odometer to read zero; and
(2)the owner of the vehicle or agent of the owner shall attach a written notice to the left door frame of the vehicle specifying the mileage before the service, repair, or replacement and the date of the service, repair, or replacement.
(b)Removing or Altering Notice.–
A person may not, with intent to defraud, remove or alter a notice attached to a motor vehicle as required by this section.
(Pub. L. 103—272, § 1(e), July 5, 1994, 108 Stat. 1049.)
And then if you're still awake there is the mileage disclosure statement that comes into play when you sell the vehicle. And there are some attorneys who claim it doesn't apply to vehicles over 10 years in age and if you simply write "exempt" you can ignore that disclosure statement or you can tell the buyer all you know about the mileage numbers from the past. Which (if they are correct pretty well gives 10+ year old vehicles a hall pass):
https://tinyurl.com/wp5mjnay But hold on a minute...can you rely on that 10 year stuff? Well, not in Texas and possibly not in your state, either. January 1, 2021 Texas adopted a brand new state law increasing the age to 20 years. So a vehicle made in 2003 would be exempt but a vehicle made in 2004 wouldn't be. And if you're coming from out of state (from a state adhering to the 10 year plan) and you have for example a 2011 vehicle which (in your previous state) was legal with an "exempt" mileage disclosure statement then we're just going to assume nobody in the world really knows and we'll mark it Not Actual Mileage for the Texas title.
So what is the deal here? I don't know but I would do my best to retain the mileage amount on the speedometer before you do anything. In my particular case that's a complete impossibility. Somebody who owned my pickup in California replaced the speedometer when the original one died with another used one. I know that because the date stamped on the back was 1953 when I removed it. And when that one croaked I went to a junkyard and bought a replacement used speedometer (one from 1951 or 1952...can't recall now) which had fewer miles than the one which had died (which wasn't correct anyway). And when I changed transmission, I went with an electronic one (for accuracy) and later replaced it with a GPS unit (for even more accuracy)...but with those electronic units you can not alter the mileage unless you own some really sophisticated equipment. So I can give an honest statement of what I think it is, but remember...I have no earthly idea what the mileage on that original speedometer that failed in CA was.
So I would sincerely suggest you check the laws in the great state of Georgia before you do anything.