Speedometer gears

[irockidz28]

ok so im sick of my speedo being wrong and putting a shit ton of extra miles on the car that im not actually driving so heres the deal .....when i bought the car the speedometer was not working properly so as part of the purchasing deal the previous owner was to fix it he said that he had already orderd the parts anyways...anyways some how the wrong drive gear got installed...i have the factory one that is 15 teeth and the one that is in the car has 17 teeth..the driven gear has 38 teeth but according to the research i have done mine should have 41 teeth on the driven gear but on the site i was ordering the gears from have two seperate housings one for gears with under 39 teeth and one for over 40...now i beleive that it is the original housing but im not 100% sure on that

so does anyone have any experience with this that can figure out exatly what i need?

700R4 trans
3.23 rear
245/50R16 tire which i think is a 24 inch tire? 25 inch??? idk for sure
speedometer revs per mile i think may be 1000? but have also read that it could be 2000???

so yea i have no clue what i really need..if i have to i can take apart my dads car and see what he has cuz it is identical to mine but he would be bull shit at me for messing with his car lol