The timing chain tensioners aren't too tough to tackle, but I don't think that you can swap out a tensioner without removing the cams. To do that after you get the intake manifold off you're gonna have to tear off the top timing belt cover, loosen up the timing belt and slip it off the cam belt sprockets, and remove the sprocket from the end of the cam. Then you'll remove you journal caps from the cams and the bolts that are holding down the tensioner and remove the cams with the chain and tensioner attached.
Just be sure you double check and trip check that your cams are aligned right when you go to put them back in. It'll take a little patience to get the new tensioner in place and line up the timing marks on the chain with the timing marks on the chain sprockets. Bolt the cams and tensioner back in, line up the timing belt sprockets on both heads with the marks on the belt, and line up your crank sprocket mark with the mark on the oil pump. That reminds me...... looks like you'll also need to remove the crank pulley and lower timing cover as well to finish the job (for lining up the #1 piston at top dead center). That part can be tedious.
The most difficult part of all this I'm sure will be finding the parts. I'm almost positive that you can't find the tensioners nor chains new. And to find them used you're gonna have to start searching on the "for sale" sections of the SHO forums, and maybe
www.car-part.com. Good luck and hope all of that info helps!
-Andrew
P.S. While working on this job it will in now way make it easier to get into the tranny to change the clutch. That's a whole different job which starts with removing a totally different list of parts. You're either gonna have to drop the subframe out from under the car after unbolting the transmission from the motor, or pull the engine and tranny together from the top. Not a fun nor easy job either way. If you can find someone/somewhere that will do it for $250-$350 in labor it would be WELL worth it. Not worthdoing it on your own just to say you can do it, or to become more familiar with your drivetrain.
I had my engine and tranny out for an engine rebuild, and I replaced the flywheel, clutch, and pressure plate in the process. Bolted everything back together after following detailed instructions, dropped the motor and tranny back in the car, and ended up with clutch problems. So that's something I'll be tackling when I take my block back out here within the next few weeks.
