Upgraded OE Valve Covers

[66 C10 383]

When I bought my 5.3 for my LS swap into my 66 I pulled the stock intake off so it wouldn't get damaged. I noticed a fair amount of oil in the throttle body and inside the intake. I later read this is a common problem along with a small bit of oil consumption.

I've seen where GM has issued 2 different driver side valve covers to remedy this. They show the 12570427 cover as a replacement for the 2007-2008 model years and the 12642655 for the 2009-2011 model years.

My engine is a 1999 - 2001 (judging by the stock composite non-riveted head gasket) and according to Rockauto, the replacement valve cover is the 12570427.

The 12570427 from GM is 142.00 and the Dorman version is 53.00. For the newer style 12642655 from GM is 77.00 and the Dorman version is 57.00.

My thoughts were to go to the salvage yard and grab the newer 12642655 since they were on all 5.3 since 2011 or 2012 and the older 12570427, since they were a replacement might be harder to run across in the yards.

I can't seem to find much difference between the 2 covers other than the pcv fitting hose size. Does it really make a difference which cover I use or should I stick with the 12570427 cover?

On the Silverado/Sierra form they still recommend running the catch can which I probably will and I've already bought the LS6 style vallry cover which is supposed to help this too.

[A1971Blazer]

On my LS1, I bought the LS6 valley cover; so far, 1900 miles, it's not showing any sign of excessive oil into the intake.

[66 C10 383]

Originally Posted by A1971Blazer

On my LS1, I bought the LS6 valley cover; so far, 1900 miles, it's not showing any sign of excessive oil into the intake.

Cool deal, thanks for the reply.

I guess from what I've later seen you run the LS6 cover and run it to a catch can and the pcv valve is bypassed. If the catch can isn't vented you use one of the valve covers for fresh air.