Just thought I'd relate what I saw recently...............................................Sorry its so long,but its a worth reading post!..friend has a 1968 Chevelle come in his shop,that is a very minty car,probably an 8 out of ten,despite it being driven year round daily (only car the owner has registered now!)...has the original 327 in it,not clocked yet either!....my friend has done lots of work on it before--he installed a new Edelbrock camshaft,lifters,valve springs and seals 2 years back--the cam lost a lobe after only 2500 miles or so,and another was on its way out too--despite it being installed right,the proper break in lube used ,and the right procedure (friend has 20+years experience and has done dozens of cam & lifter jobs)....he was puzzled as to why it failed so soon,we figured poor hardening on the lobes perhaps,or the oil didn't have enough zinc maybe???...................................................................................................................................................................................................Anyway,he buys a new Melling cam this time (stock replacement,not a hi-perf one)...and it comes with new Melling lifters,so he tears it down and puts the cam & lifters in it...car once again runs great,owner is happy,and the car isnt seen in maybe a year since that job ,other than to fix a fried fusible link....................................................................................................The owner called him.says his valve cover "cracked" ,and was leaking (had cheap aluminum covers that sucked anyway,they made trouble with the altenator bracketry),so he put the GM ones back on it ,and used RTV on top of the old gaskets still glued to the covers,and ends up twisting 2 bolts off in the head!..no biggie,my friend says he'll have to drill and re-tap the holes,and get new valve covers.................................................................................................when the car arrived,it didn't have the right breather setup,it did have a PCV valve in the filler cap,some hot rod custom thing,and another one on the other valve cover with another PCV valve in it!--but no vacuum source to it...and blowby is huffing out of it,when air should be being sucked IN to it...we noticed oil was leaking from the timing cover seal too,but it almost stopped when I pulled the breather cap off,so evidently the crankcase had pressure building up in it......................................................................................................My friend said he removed the busted bolts after a few hours of drilling and swearing,welding,etc,but it came out good...he said each valve cover looked like they had a whole tube of RTV applied to them,and there was a bunch that got squeezed out onto the head and all over the push rods,valve springs,etc..took him quite awhile to carefully remove all of it,using a scraper and shop vac ,trying not to lose any down in the lifter gallery.....................he installs the new valve covers (cheap tin chromed autozone apecials--eeech!),he said he started it up,it ran nice and sounded good for about 30 seconds or so,then a lifter starts to clatter!.............
...he figured maybe a rocker arm hit the covers,so he pulled them both off again,but found NO marks where it might have touched--and it STILL tapped with it running with NO covers too!--so now what????????........................................................................................car has decent oil pressure,but I'm betting it may have been run low on oil due to the seal leak,and the cam may be losing a lobe,but the weird thing is,all the rockers have equal travel,no bent pushrods either.we pulled them all out and rolled them on glass--and no other apparent issues with rockers or balls,or studs pulling out of the heads......we even tried removing the fuel pump to see if it was clacking ,I had that happen once on my K5's 350..............guess it has a lot of RTV stuck in a lifter or the oil galley feeding them,but it seems to have decent flow to all the rocker arms,which are fed by the lifters....................the engine also has a weird sound when you shut it off on the last revolution,like it has a lot of valve lash somewhere,but they are all adjusted to specs..................................................................................................my brother suggested maybe one of the lifter bores are sloppy,he's run into engines the factory "fixed" by boring the lifter holes .010 oversized,and GM was "sometimes" nice enough to tell you by stamping ".010" on the lifter galley....now I'm wondering if that the case on this 327???........
................my friend said he's "done" fixing it in the car,said the owner should yank it out and rebuild it right,or buy a running motor and shove the original "matching number" one under a bench,in his shed,etc......of course he has no money for that!..................................................................................................It could be that its just a lifter too,but I dont think driving it will make it "go away",it sounds like its getting worse the longer you run it!..........lesson here is dont use too much RTV on those gaskets!!...it can BITE you hard in the wallet!....
...he figured maybe a rocker arm hit the covers,so he pulled them both off again,but found NO marks where it might have touched--and it STILL tapped with it running with NO covers too!--so now what????????........................................................................................car has decent oil pressure,but I'm betting it may have been run low on oil due to the seal leak,and the cam may be losing a lobe,but the weird thing is,all the rockers have equal travel,no bent pushrods either.we pulled them all out and rolled them on glass--and no other apparent issues with rockers or balls,or studs pulling out of the heads......we even tried removing the fuel pump to see if it was clacking ,I had that happen once on my K5's 350..............guess it has a lot of RTV stuck in a lifter or the oil galley feeding them,but it seems to have decent flow to all the rocker arms,which are fed by the lifters....................the engine also has a weird sound when you shut it off on the last revolution,like it has a lot of valve lash somewhere,but they are all adjusted to specs..................................................................................................my brother suggested maybe one of the lifter bores are sloppy,he's run into engines the factory "fixed" by boring the lifter holes .010 oversized,and GM was "sometimes" nice enough to tell you by stamping ".010" on the lifter galley....now I'm wondering if that the case on this 327???........................my friend said he's "done" fixing it in the car,said the owner should yank it out and rebuild it right,or buy a running motor and shove the original "matching number" one under a bench,in his shed,etc......of course he has no money for that!..................................................................................................It could be that its just a lifter too,but I dont think driving it will make it "go away",it sounds like its getting worse the longer you run it!..........lesson here is dont use too much RTV on those gaskets!!...it can BITE you hard in the wallet!....
pull pan and found bottom full of 1-2 tubes of blue rtv and oil pickup packed full also. 
,swore by Indian Head. He also told me the hottest motor at the race,and a sure bet,was a 283 with a hairline crack....said to bet pink slips on it that night then retire it the next day 'cuz it made its grand exit....wish I were a 10th as good a mechanic as he was....
