V8 Valley gasket, Tin or Composite?

[AM400]

I need to replace the valley gasket on my 400se. The original tin gasket is starting to rust up. Having searched around the net I am now more confused then ever as to which gasket to use and wether the gasket needs to be sealed. I was going to opt for the composite gasket which I understood to be a much better seal, but I have read threads of people using a sealer and conflicts as to which sealer should be used. I have also seen bolt tightening sequences mentioned along with higher than normal torque figures

Can anyone give me a definative answer as to the process of replacing a valley gasket?

Cheers

[tr7v8]

My ten pence worth. I've always used tin ones. I pre-curve the gasket across a bin or something with a reasonable curvature. Make sure the metal bars that fit each end aren't misshaped, they tend to get overtightened & distorted. Then a film of Copper High temp silicon on all mating surfaces, including the rubber strips. Assemble & don't crank everything down solid, take your time and with everything finger tight give it 30 minutes for a tea or coffee to allow the RTV to flash off. Then tighten down front & back & torque manifold down. Mine never leaked despite running heavily skimmed heads on mine, which distort the valley gasket.

[Boosted LS1]

Go for the composite. As for sealer, it's normal to put a dab in the corners where the heads meat the valley joints. Whichever gasket you use make sure it's not obstructing the inlet ports.

[Steve_D]

If the engine is running O2 sensors then make sure any silicone/RTV sealant is 'oxygen sensor safe' otherwise the outgas from the sealant will muller the O2 sensor.
I use ProSeal which comes in an aerosol dispenser that works very well and is easy to apply in a controlled fashion.

Steve

[stevieturbo]

Composite every time.

[AM400]

Thanks for the comments and tips, I will be going for the composite and hopefully no problems!

Cheers