A500/42RH Trans Fluid Level

So you need to start out with a matched set, be it 42RH, truck, 904, whatever. Just need a dipstick in the tube it left the factory with. Measure from the point where the the tube registers to the transmission case to the full and add lines on the stick. Then put the stick you want into the tube you want and verify or remark as needed. Best bet is to just keep the tube and stick together as a set. Small block tubes will physically interchange, bit later sticks have better top seals.

The hole in the case was in the same spot for all aluminum torqueflites which keeps it simple. Deeper pans have the same full level. That is, there is just more fluid below the full mark on a deep (later truck) pan.