When to O'Reilly's and picked up the oil pan gasket for my 1986 Gt, only to find that there were two different designed engines made in 1986 (especially) in the oil pan area. And of course mine was what they call a pre-86. If the car would have been made later in the year it would have been able to use the all rubberized gasket. BUT since it was the earlier model all I can find is CORK gasket with a rubber gasket at one end. Well, I have decide to try something different. Everyone has stated to try and Not use the cork gasket due to a leakage problem in the near future. My solution is as follows: 1) I still purchased a cork gasket - Only because (A) I need the front rubber gasket no matter whether I go cork or something else and (B) I will the cork gasket as a template for my new fiber gasket.
2) NAPA sold me a roll of fiber gasket material (you can purchase it in two thicknesses). I choose the thinner sheet only because I plan on using the best RT V sealant over the gasket will help me seal it. At least I hope it does??
3) After using the cork gasket as a template. I will cut it out with an exact o knife and use a hand paper puncher to place the bolt holes in it.
4) After checking for fit, I will place RT V on both sides of the gasket and the half moon rubber gasket, then install it.
This is note worthy -- O'Reilly's can sell you four plastic screws. Each screw has a latch, which allow the parts to be suspended about 1" from the underside of the engine. This basically allows you to use your hands to start bolting up the pan to the underside of the engine, without worrying whether you will drop the pan before you get the first bolt in.
Sounds like a pretty reasonable idea, the toughest part will probably be getting the gasket to sit still while you trace it. I did mine about a year and a half ago and I used the cork gasket and didn't have any problems. I made sure I had a decent amount of RTV on it and torqued the bolts to the right spec - the torque specs on the pan are incredibly low, in fact I had to borrow a wrench because mine didn't go down below 20, which I think was ok for the larger ones but the smaller bolts were 8 or something like that. The biggest problem I had was I thought I got the wrong gasket because the holes didn't line up. I had it backwards, didn't realize the bolt holes aren't symmetrical from side to side..... D'oh!!
I rebuilt my Duke 5 years ago. I didn't use ANY Pan "Gasket", just a good bead of "Permatex Gasket Maker". Not a leak since. Just make sure both the block and pan are perfectly CLEAN.