It doesn't look like fun,anyone done it?..what should I put in it, its an SSEI...

I use a double ball swivel setup....use OEM plugs.....replace wires too.....

Flex head ratchet works fine for me on the rear bank of the 3800'*.

Flex head ratchet is what I use on my 3800 II PA.

Also reccomend OE plugs and wires, I use AC Delco, best plugs to go with IMO are the iridium plugs.

Rockauto has a rebate going on for the Iridium plugs at the moment.
ACDELCO Part # 41101
Here is a link to info on the rebate, and the link for the rebate form, scroll down a little to find ACDelco Spark Plug Rebate info.
RockAuto Current Promotions and Manufacturer Rebates

Spark Plug Wire Kit is ACDELCO Part # 746EE

I use to use a flex head.....but once you buy a ball swivel spark plug socket, and add another ball swivel to it, just add an extension to the setup and you can get to just about any spark plug.....you are limited with the throw of the flex head in tight spots....the double swivel and extension eliminates it.....easy peasy lemon squeezy....

I recommend a big old nasty comforter. To place between you and the top of the engine while replace the rear plugs. Keeps you from damaging the parts and top of the engine and keeps those parts from hurting you, getting caught on your clothes, etc.

havent done a hbody after 2000, did they put something in there? my 98 you have room for a normal wrench and my fat arms. i think i may have used a couple inch extention to clear the o2