F350 Cab swap

[Vik101]

I purchased a good running 93 F350 4wd diesel truck last year for snow plowing and the truck did great its first season. Engine is strong but the cab was shot. So this summer I found a real cheap 95 f150 2wd cab with hardly any rust, so the challenge began.
Pulled the old cab and front clip off, cut the floor for manual trans and 4x4 shifter in the new donor cab, then set in on the old chasis. I needed a new core support and found a used clean one for the diesel. Removed the EEC for gas engine, reinstalled lights/diesel wiring harness into donor front clip, installed clutch pedal, removed steering column from donor and installed the old one. Also removed gas instrument cluster and installed diesel cluster from old truck.
I must say that it all went easier than I had expected.
But......
Of course it wasn't without a glitch or two.
The wiring harness in the dash was not switched out, so the f150 95 harness from the firewall to instrument cluster is not matched to the 93 instrument cluster. What works?
The tach, instrument lights, volts, turn signals, 4x4 light!, speedo. No idea yet on the oil pressure and temp so I'm going to install mechanical gauges for those 2. But the kicker is the fuel gauge does not work.
Front tank full it shows empty. And when switched to the rear tank (empty) the needle spikes all the way beyond full.
Is the fix to buy a 95 diesel instrument cluster, or to trace the wires into the instrument plug and switch wires there?
Thanks for reading and for any info u can offer.
Heres a pic midway thru...

[ryandamo]

so your using the fuel tanks that came with the 93 along with the dash that came with the 93?

[Vik101]

The chassis and tanks are from the 93. The cab and interior including the dash and any wiring inside the cab is the 95. I swapped out the instrument cluster from the 93 cab and put it in the 95 (the diesel has a tach were as the 95 gas did not).