Hey Fixxer I have seen valve guides set up too tight on boat engines and the valves stick hot and bend pushrods only leaving minor marks on the piston tops that you might not see with the bore scope. Also are you using a fibre optic provision or a camera bore scope the camera will show so much more that the provision 100 will and you might not see the marks I am talking about until you pull the heads. I hope you pull the heads to be sure.
Thumper
Pm or call me. You need to get those valve covers back on and you back in the water!!!

i will let you guys know tonight. i am going to perform a leakdown test on each cylinder. i just have to wait until i get off and i need to clear one of my bays here so i can pull my truck straight through. the tech ahead of has nothing on his hoist today.

the results are in! 8% leakdown cold and i had no idea of where the piston was sitting in the bore (the rockers are off so the valves were closed) i poured in a little oil and it dropped to about 6-7% so my valves are good! now im just wondering if should pull the intake to adjust the valves.... and what kind of pushrods do you guys run? i know chro-moly is the best. but will standard pushrods do the trick?

I have always used 3/8 crome molly 1 piece puchrods.

I would pull the intake more so to inspect the lifters and make sure none of them got damaged.

i fixed it today... all looked good. i removed the intake just to set the valves and be sure. anyways i removed all the plugs... the last time this thing was running it was at high rpm. theni shut her down. well the plugs are bleach white. i was going to do a plug check in like 1 minute from the time it failed. i think that cylinder was just the one to go... i think it got too hot and the valves got seized in the guides. all is good now. no scoring on the valves or ghudes. just need to do a little carb tuning. this time right away.

fixxxer22,the pushrods with the balls welded on the ends are not strong enough for that cam.get the comp cams 1 peice pushrod .375 dia with .080 wall thickness.also,if you did not install the correct springs when you updated cams,IT WILL FAIL AGAIN.if wou are unsure about how to determin the correct pushrod length,don,t guess,get help from someone who knows.usually it takes piston to valve contact to bend or brake a new pushrod.i hope you get it figured out,good luck.

i installed new pushrods, crower rocker arms, arp locknuts and adjusted it twice. i was easy on it last night and just went for a booze cruise. only had to pour the coals to it a few times to pass barges and such but she is holding together. it was running for about 3 hours last night and no problems. im letting it kinda break in. never exceeded 3000 rpm for over 1 minute. the rest was all off plane 1000rpm putzing. and i upped the jets to 82 in the front and 94 in the rear. it was too lean before. i think wat happend is that was just the cylinder to go... the fuel mixture was too lean and the valve got seized in the guide.

thanks thumper, she is doing ok for now.