2.8 3.1 heads the same?

the old 88 regal has been taken out of service, bought a 2000 park ave 99,883 on the clock perfect on the inside and out just needed rear brake pads, $4500.00 this has been a few months. now it is time to tackle the regal exhaust valve lifter broke (AGAIN) cyl 3 i think? front of car middle cylander replaced all lifters a year ago ran great until june it seems like valve it self seizes in the head had to remove catilitic converter.. floored and only doing 20 mph... replaced with flex pipe my question will a head from a 3.1 liter fit and work on a 2.8???