Well if all you can get is cork, then I would suggest trying the method I used on the infamously leaky buick 231 v6 valve cover gaskets.
clean the pan surface, a course wire wheel is nice, leaves some scratches for better adhesion. flatten out all the bolt hole areas, this is pretty crucial, you want a flat surface all the way around. (possibly the biggest reason the 87/88 seal better is the gasket actually has little metal inserts for the bolts to prevent over compression) wipe it down with some alcohol or acetone to clean off all the oil residue.
get a tube of permatex ultra blue. put a layer around the pan lip, about 1/8 thick, and the width of the screw nozzle (about 1/4 inch).
Note this is one time I don't stress minimalism! put the gasket on, use the bolts to align the holes and press it down all around fairly firmly. use a small plastic spreader to fillet the inside edge to the pan side if the gasket overhangs. now put the assembly gasket down on a flat object, and put a brick on it. for the curved end, attach the gasket piece there and tape it in place, being sure that the parts where it meets is filled with rtv. let it set overnite. be sure the bolt holes are all lined up. Next day, paint the rest of the gasket with a thin layer of the rtv, and smooth it out. be sure to seal the gasket completely, sides and top with this thin layer. set aside to dry for a few hours. now carefully clean the block, I would use some scotch brite medium pads to clean off any previous adhesives, and then wipe down with some solvent to be sure all oil is off. when ready put a paper thin layer of rtv on the block all the way around, with a touch extra at those pesky bearing arch corners. install the pan and finger tighten the bolts, about 1/4 of the final tightening.
let it sit a couple hours while doing other stuff under there for the re-assembly. then tighten it to the correct torque.
may seem like alot of work, but that took care of a horrendous problem, and I reused the gaskets about 10 times without leaks. when you remove it, the thin last rtv usually remains stuck to the block, and is easily cleaned off.
that said, I hate cork gaskets, as it is way too easy to overtighten the bolts and damage the gasket. the painting with rtv seems to strengthen them and make them more tolerant of slight over tightening.
[This message has been edited by tjm4fun (edited 04-07-2008).]