Which manifold gasket?

I've replaced the intake manifold on my '98 with the nicer 99+ manifold, also doing the APN header swap at the same time. Somewhere I'm getting an exhaust leak, I can hear the "fffftttt, fffftttt, fffftttt", but I can't place it. I noticed when buying the manifold gasket that they sell one for 91-98, and then one for 99+, with different part numbers. Is this difference related to the difference in the head, or in the manifold? Which should I use?

as far as i know there isnt a difference but there might be since the two different part numbers. now i have a 97 xj that i did the same as u put the newer style intake manifold and a Banks header and i got a leak too but it was due to a tear that i made in the gasket when re-installing the old intake manifold so i replaced the gasket when i put the new intake manifold on that i got from autozone just a standard OEM replacement and i have been fine ever since. ur leak can be due to a number of things like a tear in the gasket or maybe the bolts arent tight enough or if you didnt tighten the bolts down in the right order or ur header or intake manifold flages might not be 100% true flat accross. i would start by checking out the gasket to see if there is a tear

Yes there are different ones. Ran he one they gave me with a New Dorman header and it blew out in 6 months. Thought I cracked the header , but it was actually the gasket. I put in a Pacesetter, but bought a felpro gasket with the metal around the ports on the gasket. The pasesetter one didn't have the metal edge either. That is a lot of work to have to do once every 6 months. :compwork:
Make sure you get a good gasket is my point. I'm not sure if the HO engines have different gaskets or not.