Higher RPM after Motor + 5 speed swap?

[earlingy]

I removed a KA24E with an automatic from a 90 240SX and put in a KA24E with a manual from a 89 240SX. I wired the park/neutral sensor back into itself, and it starts. I wired the reverse lights just like the write-ups showed, although the reverse lights do not work. Otherwise, it drives great, I didn't have any issues with hardware, etc.
However, the RPM is much higher to cruise on the highway. 3000RPM is like 58mph, 70 is like 3800rpm. I am wondering if the rear differential is different on auto vs. manual? The 90 auto had some sport package (spoiler and alloys), and the 89 manual did not. Could it also be the tachometer? The 89 did have like some luxury package with the digital speedometer, HUD, and power everything, and 90 does not.
I can't really say for sure whether it sounds like it's at a higher RPM than it was in the other car since the new exhaust is different. I still have the other car, so I have all the parts still. I could change out the tachometer, digital speedo, or ECU, assuming it would clip in- does anyone know if those things would clip right in? Just another random question... Would the power windows/locks/etc clip right in as well if I were to just switch the doors?
Thanks!
Alex

[biggie]

Diff is the same.

Did you use the Manual Speed Sensor?

[earlingy]

No, but i had gps verified my speedo in the 89m pre swap. I gps verified post swap and the speedo is correct still...

[biggie]

Your speedo can't be correct if you are using a AT speed sensor in MT.

[earlingy]

Oh, sorry I thought you meant the AT speedometer. Yes, I never disconnected the speed sensor from the transmission. It's still in there and the speedometer is correct. Now that I have the factory exhaust on the car, I'm pretty sure the tachometer is reading high. I have the digital cluster, I think I'm going to swap that in- any other ideas?

[Justinians_2:40]

I don't know much about the automatics, but my first guess would be that the automatic had a higher overdrive gear, you have to remember that these are two completely different transmissions and the gear ratios are going to be different.

[earlingy]

I agree, the overdrive gear on automatics is higher. But the higher RPM is being compared to when I drove the 89 manual before it was wrecked, compared to the 90 automatic chassis with the motor/trans from the 89 manual. Understand what I'm asking?
Thanks

[SX APPEAL]

With all stock gearing and the 5 speed you should be turning roughly 3K at 70mph in 5th. Sounds like your tach is reading high for some reason.

[earlingy]

Right...so...any ideas? This weekend I'm going to swap in the digital speedo cluster from the 89...dunno where else to start. Maybe the ECU?

[earlingy]

Digital speedo cluster swapped in, now it reads correctly.