GV Under/Overdrive Units

are there any clearance issues with the gear vendors unit in an a body? I have been thinking of installing one in my 4 speed dart for a while now but I don't want to have to cut it up.

I ended up lowering my trans mount 1/2 to 3/4 of a inch to get mine to fit without tunnel modification. 68 Dart 360/904. It was that or heavy hammering on the tunnel. Didn't like either option. The gear vendor is great other than that.