Which is the best valley pan gasket, rubber or composite?  When you install the gasket, is it recommend you use a sealant on both sides before you tighten the valley pan down?

Darrell Howard Whitefish, MT Outlaw 56 Ford F-100's

Unless you PLAN to remove the pan for some reason, best gasket is none at all. A bead of oil resistant silicon only has two surfaces to seal (a gasket has 4).

6 VOLTS/POS. GRD. NW INDIANA

Whatever way you choose to do this:the pan retaining bolts are only supposed to be tightened to about 2-3 foot pounds which is basically just snug.Overtighteng distorts the pan and causes leaks.Check your surface for flatness.Most are warped from overtightening.

  

When given the choice, I prefer the composite gasket with K&W Coppercoat on the bottom side and a thin film of RTV on the top side.  And as has been mentioned, watch out for overtightening of the two bolts holding the valley cover in place.  The plus side to the rubber gasket is that it can sometimes be reused whereas the composition gasket if put on with sealer so it will not leak is typically a one shot deal.

Lorena, Texas (South of Waco)