NO! silicone is NOT the correct sealant
BTW I have on several occasions seen guys who complain about various oil leaks on valve covers and rear seals ETC.
Used, engine parts will have oil embedded deeply into the micro surfaces.
almost all replacement parts will have a wax or grease preservative coating to prevent corrosion during shipping!
IF YOU simply wipe off oil soaked surfaces with a paper towel, who then smear on the sealant of there choice and proceed to install gaskets,
YOU WILL OCCASIONALLY HAVE LEAKS!
and then they wonder or maybe be in shock when you find the seeping oil leak has returned in a few weeks time!
metal surfaces may look smooth as glass but under a microscope they look like the surface of the moon , with lots of jagged surface cracks, so you really need to wash out the micro lubricants trapped in those cracks with a thin fast evaporating grease solvent and a lint free rag , followed by a second repeat of the process and in many cases a few minutes with a heat gun to dry and evaporate the solvent in the micro cracks ,
STOP AND READ THE SEALANT PACKAGE DIRECTIONS!
you'll generally find some rather amazing , bits of info such as temperature requirements, temperature limitations, what solvents work best to remove the cement or sealant, only after reading the directions, do you then smear the gasket sealant on both mating surfaces before bonding the two gasket & metal surfaces.(and in many cases you use a brush as dirt or oil on fingers prevents a good seal!)
pontiac
http://www.boxwrench.net/specs/pont_265-455.htm
chevy sb
http://www.boxwrench.net/specs/chevy_sb.htm
chevy BB
http://www.boxwrench.net/specs/chevy_bb.htm
426hemi
http://www.boxwrench.net/specs/hemi_426.htm
383-440 mopar
http://www.boxwrench.net/specs/bchrys_B.htm
318-340-360 mopar
http://www.boxwrench.net/specs/schrys_A.htm
ford 429-460
http://www.boxwrench.net/specs/ford_429-514.htm
302-351 windsor ford
http://www.boxwrench.net/specs/ford_302_351W.htm
351 cleveland ford
http://www.boxwrench.net/specs/ford_351C.htm
352-428 ford
http://www.boxwrench.net/specs/ford_352-428.htm
read thru these threads for more info
viewtopic.php?f=44&t=846&p=1284&hilit=sealant#p1284
viewtopic.php?f=50&t=50&p=1253&hilit=sealant#p1253
first step is to remove the old freeze plug and accurately measure it, FREEZE plugs generally come in either zinc plated steel or BRASS, both work, but the steel deteriorates rapidly if you don,t use a 50% mix of anti-freeze in the coolant.
Once you know the correct size you then visit the local auto parts store and buy both a BRASS freeze plug of the proper size and the correct sealant.
Personally Id buy a complete set of brass freeze plugs and replace as many as you can easily access if they are STEEL, with the far more durable BRASS VERSIONS and next time the engines out of the car Id damn sure replace the rest.
having a seal or bearing driver tool to seat the freeze plugs correctly after brushing sealant on the block and edge of the BRASS freeze plug is helpful
http://www.harborfreight.com/18-piece-seal-driver-kit-35555.html
that .032--.039 hole in the pass side oil passage plug will be Just fine !
the object off drilling the tiny hole for those that don,t know is two fold, first it prevent trapped air in the oil passage from slowing oil reaching the lifters as trapped air is bled off rapidly, secondly it provides a constant flow of extra lube flowing to the chain cam drive even at low rpms