So lets look at the size of both fleets when they signed the Washington Naval Treaty in 1923. This is a good stopping point as it represents the last point that the size of the fleets was based only on national policy and capability. Under the Treaties(Washington, First and Second London) which ended in 1936 the USN and RN were arguably kept artificially closer in strength to the IJN under the 5:5:3 rule which was beneficial to Japan and the world in preventing another Dreadnought Race.

When she signed the treaty the USN had at its disposal, 21 Pre Dreadnought Battleships, which while useless in the battleline were useful for secondary duties and the fact that their presence allowed Battleship Divisions of modern ships to be elsewhere.

She had in commission 19 Dreadnoughts, with 4 of the West Virginia class almost done(3 would be finished), along with 6 of the original South Dakota class which were scrapped. The last 12 of these ships(from the Nevada on) were known as the "Standard Type" battleships with similar characteristics for gunnery, armor protection, speed, and range. This was important as it gave the USN by far the most uniform battle line in the world at the time, meaning an Admiral did not need to account for each individual ship's features, what one could do they all could do.

Also scrapped were the 6 ships of the Lexington class of Battlecruisers. First desired in 1911 in response to the Kongo's, their development had been drawn out, and construction of other lighter ships prioritized, while the design was refined with data from the RN after Jutland. 2 of the hulls were converted(Lexington and Saratoga) into the first true fleet carriers of the US, and at the time the largest warships afloat.

Her cruiser force however was badly lacking in modern ships, while having plenty of large, older armored cruisers, she had just the 10 new Omaha's for use as light cruisers for scout and escort work.

The Destroyer force though was newly built and massive, the 267 ships of the combined Wickes/Clemson classes were knwon the "Flush Deckers or 1,000 Tonners". They were fast and long ranged for fleet escort work, while retaining some anti sub abilities. And while the RN could put a similar number into service if needed they were old and rather motley across many different classes of evolving capabilities.

Against this Japan at the time had 14 Pre Dreadnoughts, 5 of which were captured prizes from the Russo-Japanese War and of limited uniformity wit the rest and each other.

However she had just 7 Dreadnoughts, and while the Nagato class were arguably the best warships of the 1920's they were still just 2, and the IJN battle line lacked both in size and uniform composition if it desired to include the older ships.

The 4 Kongo's were first rate Battlecruisers and built to a British design, but retained all the flaws of the type, as their rebuilding was not for another decade. However they did give the IJN a true fast wing of the battleline in the British model that the USN did not include in doctrine.

Scrapped at the time had been parts of the 8-8 Fleet planned, including 2 Tosa class BB's, 4 Amagi class BC's, and the first two Kii class BB's. The scrapping of the mostly complete hull of the Tosa was seen as a day of national mourning and did much to sour Japanese opinion of arms treaties as her construction had in part been funded by public subscription. However the Akagi and Kaga were both converted into carriers, and would form the 1st Carrier Division with Akagi the future flagship of the Kido Butai.

Her cruisers consisted of about 20 or so older gaggle of vessels, including again a few Russian prizes, including 4 larger armored cruisers that were considered prototype BC's. She was however building what would be eventually 16 new modern light cruisers with powerful torpedo armaments.

She had about 45 modern destroyers under construction between the Kamikaze and Minekaze classes, along with about 50 second class DD's meant for escort or less dangerous roles.

So looking at the balance of power across the Pacific just before the Treaty Era while Japan could try to play to her plan of gradual attrition before a decisive Mahanian battle on her home turf she in many ways was beginning to or was just so far behind that she would simply be outbuilt in time if she was not able to sufficiently degrade US morale, which given the likely heavily racial and brutal nature of any war fought after by Japan after WW1 it seems unlikely.

War Plan Orange had come to maturity by that time, and was in large part the very strategy used a generation later by the men who had studied it to death like Nimitz and King. Were the year 1905 the result is very likely the same as the US had a large number of good Pre Dreds, however were it sometime around 1915 you might get a more interesting result as Japan went full bore trying to buy and build dreadnoughts, while the USN had to beg, borrow, and steal in many ways to get them built, and at first got an inferior product. But by 1920 let alone 1925 that had changed.