Before you take that engine apart I would do a leak down and figure out which cylinder is dead. Might as well fix that while you’ve got it apart of course I’m sure if you take the engine completely apart you will find out what is wrong but if you were just going to dig into the lifter valley you might want to see which head needs to come off to figure out why the cylinder is low.

Ethenol loves carbs..port engine wouldn't even idle...Took carbs apart.. soaked them in chem dip..Carb cleaner in metering blocks, blew out with air..changed all parts.. good as new.. idles and runs great.
I was told to drain the fuel bowls after winterizing.. I forgot last year lol

No cylinder is dead....?? where did this come from? last week

Thinking s different thread. I have done this s few tines too. Doh !

So, back to my last post. The carb issues diluted the oil. Change of oil got rid of noises. In your case, you said oil additive made noises a little louder ? Boat has not left dock in 2 years ? Been started and ran a bunch ? So, before tearing things apart maybe do oil change first ? Never heard lifters do this even with ratty oil, but, never heard them do it……lilolololol Anyway, should be done anyway, so……

round table talk….throwing things out there

agree see post #18

but what if the pushrods are galled and less oil is getting on top ? the rockers and balls could be worn again...

taking the zrod amsoil 20-50w out. putting in valvoline zr1 racing 20 50 reg oil for a test

Btw, your previous rockers…..Typical for those comp roller tip rockers to burn up. Seen it first hand dozen times ???? After all these years i can’t believe they still sell those piece of ****s. And, btw, on sbc, bbc, stock oil pumps, high volume, ….doesn’t matter….they suck. They over heat, smoke sometimes, turn blue..,,,horrible.

So….don’t let yourself think / include that experience for what may be happening now.

I’m going by what I hear on your clip turning the engine over. I hear an audible Low cylinder. Just figure if you’re going to take that motor apart you might as well see what it is. Could be a valve could be a gasket could be something to do with the piston and/or cylinder. But need to figure it out.

ok thanks for your input. but both motors are doing it and they run great ?

I am going to check for galling of the pushrods and rocker balls. I am also going to check the geometry. I will check the valve stem mark to make sure the rocker is riding at the center of the stem. If they are galled I may not be getting oil at the rocker at the right time.

Could the popping still be in the headers/exhaust, and you are feeling it through the exhaust valves/rockers only?