4.6l ticking and missing

I have a 1997 cvpi with 153k miles. The engine started ticking about 20k
ago. I ran seafoam through it and it made the ticking worse. It is coming from the #8 cyl. so i tried replacing the injector. The car has developed a noticable miss now. Am i right in assuming that this is a burned valve? Do I have to pull the heads to repair this and if so would i be better off doing a swap to performance improved heads while i am at it?

Hmmm...maybe. I would look at the cost and the gains from the cost. See if its benefically!

If you like the car try and get a wreck from somewhere, (paid about $1,000.00 for one with 40k on it),or a junkyard motor. I have one with 185K that my nephew blew up, I am going to rebuild it in the car, sounds like the overhead cam bearing.

on my 95 crown vic cylinder 4 was missing i replaced the plugs and wires and that did the job. if its not that then you might need a valve job which can be a pain in the ass.

Ticking AND missing may very well be an ejected cam follower. Another possible cause, while very rare, is a failed timing chain tensioner.

Until you do a compression or leak-down test, I would not "fix" anything else.

I had a ticking from my engine once, I also thought it to be my injector. Turns out the guy at the shop put the sparkplug in loose, causing the ticking noise, which eventually led the the spark plug blowing out and causing a HUGE headache that I wouldnt wish on my worse enemy.
The question is did the ticking stop when you changed the enjector. There also was a loss of power as the loss of compression. If this is the case you need to try and corect it before the threads get dammaged and you have to pull the head to fix it. Which believe me is not fun!!! GOOD LUCK, hope i have helped!