I need some advise in what is the proper way to set-up my valve covers for a 565 blower mtr. [ 871 blower shop ]. currently I have one PCV valve per cover going to each carb. Ran the boat this weekend & only went up to 5000 rpm for about one minute and it blew out the timing cover seal. Total oil mess !! PLEASE HELP !!

Should only use one PVC in one cover. Good quality breather in the other. Two PVC valves will not relieve blow by.

On my boosted engines I take the pcv valve out and put a breather in each valve cover. The pcv is only sucking when you are not in boost. Under boost the valve can leak and put pressure inside the engine blowing out seals.

Sounds like you have serious ring seal issues, do a leak down test and also get rid of the PCV and put in some bigg valve cover vents like they run on circle track that are tall, I put in 1" pipe 6 inches tall with clamp on vents on my boat, if bad ring seal put in scotch brite or steel wool in the tubes to still allow vapors out but to hopefully catch excess oil, Smitty

you can run the 2 pcv to the carbs like yo have but you have to have a vent deal to let them draw from, if you have no other venting you are sucking against the weakest seal...air has to go in to make a loop...and in a blower like that it will draw most all the time...but if have issues after that you do have a sealing issue with the rings like smitty said...

Plus sucking in oil is helping Mr deto find a home in your motor.

This is a fresh built mtr w/ only about 1hr of boating time plus dyno time. Thinking of taking the guts out of the pcv valves and running the hoses to a catch can & installing k&n clamp on filters. there was clamp on filters for the dyno pulls and it tried to push the dipstick out. maybe I just need time for the rings to seat. just trying to releave some pressure so the front seal doesn't blow out again

I agree with the above mentioned thoughts, but just double check your engine oil level. New motor, maybe overfilled? What size oil pan? I have a similar engine vented to atmosphere; 1 per cover. BTW, we're do you boat? I'm out of Hyde park on the Hudson river most of the time.

I seem to be having a similar issue with one of my pair of identical new 383 small blocks with 671's. Like yours mine were broken in on dyno, though after hours of pulls there was no blow by at all on either engine. Last Sat. at a poker run after about 45 miles under boost my' over' level oil alarm went off. after lifting the hatch I found that oil had been blown out of the breathers and into the carbs. The compression test looks good I am draining the oil now it looks clean as when it went in, no sparkles! ????.

oil rings can fail and still have good compression...a lot of blower engines need a vented puke tank for blow by...also dyno pulls are nothing close to 45 miles under boost !