I'm in the process of installing a bathtub in my basement (there is an existing rough in).
my tub is 60 x 30 inches and is 16.5 inches high. the floor to the drain opening is 2.75 inches.
I was at home depot and thought it would be much easier to get an overflow drain kit (~$20) ... but after trying 2 different ones, I can't seem to get it to fit (do they come in different sizes?).
the problem comes in the elbow at the drain. the clearance (from the floor to the drain is 2.75 inches, but the elbow is about 3". so the overflow kit is actually lifting the tub slightly from the from to the back.
does this mean I should elevate the tub slightly?
the tub comes with a foam bottom - which I understand is supposed to sit on the concrete floor.
I believe the part you are talking about is called the shoe and it is the internally threaded piece that receives the metal drain from above. I just measured one in my truck that is of tubular design (not sch.40 and connects with nuts and washers just like under your kitchen sink) and it is 2" high and probably 2 1/4" with the rubber seal. I don't know what you bought there or how high the sch.40 type is but by all means do not raise the tub, chip out some concrete to make room if necessary or get the type that I have described.