On my motor I just used diamond pistons. If you run a bigger cam than stock you'll be closer to a factory dynamic compression ratio. My static ratio was a little under 9.1:1 using a fel-pro 1000 head gasket. I like the diamond pistons over the JE's with a TTA because their dish volume is largely cut into the valve reliefs, so they have better piston to valve clearance and they take advantage of the quench area in the head as long as you have a maximum .040" Piston to head clearance.
I ordered gaskets individually because the exhaust flange is different. Get exhaust gaskets from an '86 lesabre 3.0. Just about everything else for the engine is the same as GN except for the oil cooler, and the oil pressure sending unit is different. If you get new o-rings for the oil cooler you will have to get them from a hardware store. No worries on that if it's a custom project though.
