New Bronco, mystery motor with valve noise?

[Sheehanigans]

Hey all, long time lurker as I've been learning more about the early broncos. Finally got one and I've been scratching my head over some motor noises.

The truck is a 68 and I am told the motor is a 302 from a 72. It has a two barrel holley on top that had lots of black soot residue on it and the inside of the air cleaner. I have since cleaned it and it hasn't come back as bad, so maybe not a problem now. Or maybe an indication of another problem.

I changed the spark plugs and fluids, and immediately cylinder 4 is covered in dry black carbon. The wet oil on the threads are from running the motor without the valve covers so it dribbled a little.

At idle and increasing with engine speed, there is a tick that sounds like valve tapping. I have been researching and tried to perform a valve adjustment yesterday, but once I took the covers off I had second thoughts about what kind of adjustment I needed to do. The rockers are linked in pairs with a u channel guide, and that means that this is a 78 or later, correct? Non adjustable rockers? Just torque and go? What do I have here?

Also, exhaust is separated by each cylinder bank. On this side where the noise is coming form, holding a piece of paper up to the exhaust tip sucks the paper toward the exhaust every once in a while. A friend says that means a burnt valve? What do yall think about that?

Thanks!

Spark plug 4

3

2

Other side, plug #5

Any help is greatly appreciated!

 

[BRONCROB]

I would spin your push rods to check for a bent one and then do a compression check.That soot looks to me like you may have an intake valve leaking?? or your timing is off really bad.

 

[Germd]

Does it tap more at cold idle than warm? A bad lifter that's leaking down can cause a similar tapping, so can a very small exhaust manifold leak. I use an old stethoscope with the bell removed and listen with the open end to isolate engine noises. You can also use a long screwdriver to listen by putting the handle end to your ear and touch the blade end to where you think the noise is coming from. Don't laugh - it works!
I learned a long time ago to spend a longer time diagnosing to waste less time and $$$ fixing.
Congrats on the Bronco & I'll be joining the club next weekend when I pick up the one I bought yesterday.