Oil Pan Gasket: What am I doing wrong?

I have the 300 4.9 on the stand doing a rebuild and I'm ready to put the oil pan back on and I have a gasket problem. I have a fel-pro four piece gasket. In fact, I have two. At the start of the project, I picked up a couple of gaskets individually before I ultimately decided to buy a full rebuild kit with all the gaskets (which included the same model as the one I had). So, the problem is with the rear rubber gasket. I definitely have the front one on front and the rear one on the rear, so that's not the issue. However, on the back one, there are two rubber knobs/tabs that seem to fit into a notch on either side of the rear seal/bearing. When I fit one of them in that notch and then begin working it to the other side, I end up with a half inch or so extra. If I fit both tabs into their notches, then that extra is a gap in the middle. As I said, I've tried two different units of the same model, from sealed packages, and double checked the fel-pro website for the correct model number. So, it's some kind of user error. Anybody ever run into this? What am I doing wrong?

Could you post some pics?  That might help us understand what is going on.

This one shows the whole view, without either tab pressed in


The gap left over on one side when it's fitted on the other side


The rubber tab and notch it fits in. A bit hard to see with the tacky gasket sealer clinging to it.

I don't think you are doing anything wrong  If the tabs are in place wouldn't the pan force the gasket to conform to the engine?

If you can't get the seals to work then why worry about it and just use some RTV.

Curious, not knocking your choice - why don't you use a one piece gasket? They seldom leak.

myrl883 wrote

Curious, not knocking your choice - why don't you use a one piece gasket? They seldom leak.

1987 and up.

I thought they would retrofit, but I'm not totally familiar with 300s - they tend to not  follow me home...