I need to know which is the stock size of a MLS Gasket for a M50 engine.
a).070
b).080
c).090
d).120
e).140

.070 is stock BMW Head gasket thickness...

depending on what you are doing. if it's oem spec engine and you'll be keeping it that way, then a .120 or .140 with .140 being the popular choice among most. i have a .120, if you were reducing compression via pistons then close to oem thickness will work

Now I'm confused!!! .070 or .120????! I'm reducing compression via pistons using 8.5.1 and I don’t want to reduce my compression more with a thick gasket, so I want to use the stock size to keep the compression close to, or in 8.5.1.

Now I'm confused!!! .070 or .120????! I'm reducing compression via pistons using 8.5.1 and I don’t want to reduce my compression more with a thick gasket, so I want to use the stock size to keep the compression close to, or in 8.5.1.

.070 is stock BMW Head gasket thickness...

.140 will put you at 8.9:1, which is what a lot of people use instead of pistons. The thicker the head gasket the weaker it is, which I'm sure you understand and is partially why you went with pistons. This is mainly for other people who will be searching.

.070 is the stock Head gasket thickness on the M50 engine. If you change your compression via pistons, then you could potentially use the stock hg. The MLS head gasket will hold up to some crazy boost. It is known for its strength, not its endurance. Basically you could run 9 psi or 25 psi and 6 months later the MLS will start to leak at 25 psi and 7 months it will start to leak at 9 psi.

Now I'm confused!!! .070 or .120????! I'm reducing compression via pistons using 8.5.1 and I don’t want to reduce my compression more with a thick gasket, so I want to use the stock size to keep the compression close to, or in 8.5.1.

.070 is the stock BMW size, I dont know why these guys are talking about lowing compression when you asked for the stock HG thickness..

If you have any head or block work done (resurface or deck) it is common to use a .080" gasket to make up for material removed from the head and block and avoid any possible clearance issues if you are using high lift cams. When my head and block were resurfaced/decked they removed roughly .010" from the surfaces combined.

Either way, the stock gasket is .068", so the Cometic .070" is the direct 'replacement' for it.

Thanks for the info guys!!!!!!!

Im using a 0.04 MLS :shifty

Im using a 0.04 MLS :shifty

.04 MLS? What pistons are you using (compression)?

Engine was designed to be at 8.5:1 with a 0.04 MLS.