tmccabe

Background: I got the cylinder 8 misfire and misfire in first 1000 rpm codes. Moved plugs and coils, problem didn't follow. Compression test showed 150psi on 1-7, 90 psi on #8. Wet compression test on cylinder 8 was at 180psi. Thinking it is a ring issue. Decided to do leakdown test, cylinder 5 had 4psi differential and cylinder 8 had 40psi differential. Air coming out of throttle body, pretty confident it's the intake valve (yes, I've seen the TB on it).

Truck has 180,000 km (113k miles) on it. It's my daily driver, takes me fishing (hence the 35's and winch) and pulls our TT 4-6 times a year for camping trips with friends (re-geared it to run 35's and tow moderately). I don't drive this truck like I stole it, regular maintenance performed and only use OEM filters.

Plan:
I have a machine shop lined up to rebuild the heads for me. I'll pull both heads this weekend in frame and drop them off Monday. Pick them up end of next week and have it all together before Christmas.

Q 1: I'm considering replacing the timing chains, sprockets, tensioners but I also haven't seen many posts or heard from my Ford tech buddy that there are many issues with these. Is it worth replacing?

Q 2: I ordered some BBK tuned shorty headers at a pretty good discount. Figured easy enough when I have the heads off to add, probably never do it otherwise. Worth it?

Q 3: what else would you recommend servicing while the heads are off?

Q 4: I have not found a good video on pulling heads while in frame. I've seen the "I do Cars" stuff and the "Cheeky monkey" vids. Any other good references or there or manuals?

Thanks for reading the lengthy post!

[F2C]MaDMaXX

Subbing for the progress and updates, feel free to post a load of pictures too

(this isn't common on the 5.0s, most people just replace the engine instead of doing the heads.