Gonna change my plugs this weekend. My question is how difficult is it on the 4.6 motors. I've done it a hundred times on my 5.0's. Never changed them on the newer stangs. Any hints, suggestions or problems I may run into. Also gap and what do you recommend for a plug. Thanks
NGK plugs work great in our cars. I have not had any problems with them. I would stick to the regular copper ones. Since I note that you have nitrous, I'm not sure if you need to go to a colder plug with less of a gap.
Changing the plugs is easy on the driver side bank, a little trickier on the passenger side. All that is required is to take the COP off, get an extension and take the plug out. I would recommend blowing a lot of air down in the chamber (before removing the plug) to blow out any dirt that has accumulated down there. On the passenger side, you would need to remove the plastic air intake tract from the throttle body and go to work.
my advice, (given the track record of threads pulling/stripping out of the heads) take it to a shop and have it done, that way if THEY strip the threads or it happens later on down the road, it falls in their lap, not yours. now if you must DIY, then make sure the engine is stone-cold, to avoid the stripping the threads out of the heads which is a BIG problem on these cars.
Forgot to mention to do it when the engine is cold (as previously mentioned), put anti-seize on the threads and torque to 12ft/lbs. I've done it many times with no issues.
I know everyone recommends copper plugs but I prefer platinums.
When I used autolite 764 copper's, I did not notice any change peformance but lost around 2 mpg with my usual driving.
I saw a set of 8 autolite 764 platinums on ebay for $7 shipped so I figure I should try them out. When I used the platinums, I gained back the 2 mpg that I lost. An performance was the same.
Whatever plug you choose (I have NGK TR-55 IX pre-gapped) but the point is... use duct tape to secure your socket to your flex wrench to pull your socket back out of the hole once done so your not leaving your socket head in the hole.
or else just buy a socket thats designed for a motor with recessed plugs. i have a 9" plug socket from MATCO and a 15" swivel plug socket from Harbor Freight.