Yes you can. I had a VDO 3 gauge pod that was adhesive to the flat spot on the dash right beside the Turbo gauge. I had a calibrated Turbo, oil pressure and oil temperature gauges installed. I got the pod at Summit racing. Before that I had gone to Radio Shack and got one of their project boxes and installed the oil gauges in that. It didn't look bad but could have looked better. But due to the fact that I never saw over 200 degrees F. on the oil temperature gauge and the Saab APC system is pre-set at 14 psi I went back to factory gauge in the cluster and tossed the oil temperature gauge in the parts box. The oil pressure gauge I ended up installing in the dash. It looks really good where I put it.
I installed it between the ignition switch and the climate control unit. If you decide to put one there make sure you use a gauge with the metal U type bracket to hold it in place. I had a VDO unit that had a plastic screw on like a bottle cap thingy to hold it and it was too wide. Lucky for me I had another oil pressure unit laying around with the metal bracket. If you didn't know VDO makes all of Volvo's gauges. In fact the oil temperature sender in my car is from a Volvo 240. You can get pillar pods from IPD that will fit on the A pillar between the door and the windshield and your 240 units should pop right in.

1987 745T M46 Saab APC 14 psi
Bilstein HD's, IPD 25 mm bars
U&L Chassis braces, lowered,
16 inch Hydras and only 321,000 miles.