I changed mine today for the first time (55K) fixing another problem I had. See "got it wet, now has miss" post. Thanks for the help BTW. So it is now good as new. I used Motorcraft replacement which seems like it would be important to do so because of the fairly unique ridges in the tip and the way the boot fits on them. The original plugs are not plat to plat plugs, I figured they would be since they are supposed to be good for 100K. To tell you the truth I do not see how these plugs could possible go that far. Mine were ate away pretty good with an average plug gap of .064, the new ones are .052. The manual says plug gap should be .052-.056 So, with only 55K mine were out of specs. It took me alot longer than I expected, about 4 hours and I am mechanically inclined and have alot of tools. It is tight in there but once the coil packs and boots are off ( the boot is only about 4 inches long and is part of the coil pack but it does come off) it is not that difficult(except #4) to get to the plugs. The delearship charged my buddy 120 bucks parts and labor to do it. If you can afford it I would definately recommend letting them do it but if you want to do it yourself I recommend the following tools.

10", 6", 3"(x2) 3/8 extensions.
3/8" swivel
Snap on(or other) 3/8" drive with pivot head(essential)
telescoping magnetic pickup tool(for the coil pack retaining bolts)
deep 7mm socket(for coil pack retaining bolts)
1/4" swivel

Nothing else had to come off the engine to get the coil packs out, just the retaining bolt and the electrical connection on the coil pack itself. I put dielectric around my coil pack boots to seal them against water intrusion(my original problem). Good luck.

 

If you had taken the battery leads off the power terminal and remove the 2 screws and ground wire you would have found that it drops away just far enough to get to #4 a lot easier

 

I once spent 4 hours to change the plugs in my 1970 Mercury Cougar XR7 with the 351 Modified Cleveland. The labor manual said it should only take 3/4 of an hour. I dreaded the last 2 hours and wondered why the manual said 45 minutes. I had an epiphany a week later and next plug change I removed the two motor mounts/bolts and jacked up the motor with a floor jack. Walla, it took about 45 minutes. I am dreading changing my plugs/packs and may just pay the coin to the dealer.

 

I bit the bullet and paid my local mechanic about $285 (included my oil change)...For the aggrevation saved I figure it was money well spent.

 

Tex,

the heater hoses were the prob with #4 for me, I didn't have any issues with the power distribution box on the passenger firewall.