Another question.

[ddarton]

Thanks again for those that answered my first question.
On to the next one. Below is a picture of the shower pan dry fitted into place. The issue I have, is that the stub up drain pipe was installed at a slight angle back when the house was built. The original plumbing is 1/2 inch off of where it should be, so the plumbers or whoever took and angled the stub up to correct for the error. I have a poured concrete slab. I am going to assume this is not something that is done normally. Unless of course that was normal for 1975. The plumbers then back filled around the stub up with some sort of material. Not sure what it was but it was hard and not very flexible.
Thoughts on what I should do? The shower pan is a Swanstone with a molded in place drain that uses a large black o-ring, (caulk ring as Swanstone calls it) to seal up around the stub up. The ring fits half way around the stub up but obviously not all the way around.

Shower pan

[hj]

I assume it is the backside which is too narrow, because the angle of your picture makes it look like the pipe is centered in the opening, and does not show the narrow side. That gasket does not seal properly to an angled pipe and since that is a cast iron pipe it will not "flex" to straighten it out.

[ddarton]

The pipe is actually black plastic, it is not cast iron. You are correct that the pipe is angled towards the back of the pan.