HELP ME FIGURE THIS ONE OUT! 
OK, so since yesterday the short trips around my street and all the other system testings checked ok... I decided to take the car out around town and drive it in the highway and see how the car reacted.
So I got some temporary DMV tags and when out and about riding. I put in about 20 or so city miles, and about 10 or so highway yesterday. Plus some more aggressive engine loading / city driving today to promote ring seating. (I even got the car inspected today)
So far everything works great...
EVEN THE SPEEDOMETER / ODOMETER ARE REGISTERING CORRECTLY...
And that's my problem... I was expecting my speedometer & odometer readings to be off, so from the start I downloaded a speedometer w/ odometer app on my phone so that I could track my "GPS" speed vs my "GAUGE" speed... But my dash speedometer & odometer where accurate to within 1 mph all the way though the speed spectrum up to 75phm... accurate the whole way through!!!
So of course, now my mind was racing to try to figure out why...
If I just installed a 3.52 tranny, on a formally auto car, how can my speedometer be accurate? Could it be that I was tricked and was sold a non-3.52 tranny? But it definitely came out of a four cylinder because the linkage support was in the 1.3L location...
So from the info on this web thread I came away with two things:
1- the driven (17/18 tooth) gear is basically interchangeable between different but similar diameter tire sizes... which means I could have gotten extremely lucky and have the perfect gear/tire combo for my speedometer
2- all pre'95 1.3 MT would have a 3.52 ratio, but all post'95 MT would have a 3.95 ratio
which is the same as the automatic transmission ratio originally in my car !!!
So this thread somewhat collaborates that there is a 1.3MT w/ the same final ratio (3.944/3.95) as the automatic that my car was once equipped with, except they don't classify it as pre or post '95, instead its classified as FWD?
Could I have been duped, and sold a fake!!!
So I took a look at the transmission identification markings:
M244860 M= indicates 1991
So now I was confused, pre'95... but what did FWD stand for?
Could I have a 3.944 ratio transmission? I have been unable to decode the rest of the numbers to find gear ratio.
So the next best thing is to drive at a fixed speed and obtain RPM, and tire size and do the math to figure out final drive ratio...
So I installed a little cheap universal induction RPM gauge that I had recently purchased for something else...
This is what I came away with"
1,300 rpm @ 40 mph
1,750 rpm @ 55 mph
2,100 rpm @ 60 mph
Using these figures and my tire size revs/per mile I tried multiple combinations of gear ratios and none fit the bill... It comes out that I have a final drive ration of 2:1 - 2.26:1...
which I know is not right... So now I have to question the accuracy of the RPM gauge.
HELP ME OUT... What do you guys think.