Cosworth headgasket

[samxini]

I had posted this in the KA-T section in a thread about the Cosworth head gaskets but traffic over there is pretty slow so I'll ask it here.

I was looking at the Cosworth head gaskets and I've heard nothing but great things about Cosworth but if I was boring out my motor to .020 over would these gaskets be to big for that?
They seem to only come in a 90.5mm, I've been told you want the head gasket .5mm larger than your bore size but would 1mm be too much?

[OutToWinPAHC]

I would get a proper gasket

[samxini]

And what exactly is a "proper" gasket? Keep in mind I'm shooting for about 400hp here.

Felpros can be hit or miss and I'm not sure how well they'll stand up to 400hp.
From what I've heard, Cometic can be good if your block and head are machined extremely well but they also seem to be hit or miss.

[Chaluska]

ive heard great things about cosworth.. just make sure you get the bores matched up...

felpro has a great rep also though, the headgasket is not usually the weak spot

[badbob2121]

I have a Cosworth headgasket.


Good quality

[samxini]

I have a Cosworth headgasket.
Good quality

What bore size are you running? Both motor and gasket?

I'm stuck between felpro and cosworth now. I'm not to worried about the rest of my motor, it's pretty much fully built.
But I know it all comes down to your tune.

[badbob2121]

Factory bore (86mm) and I have the 87mm/1.5 gasket

[krash]

A lot of people have good things to say about the OEM felpro on their KA-T setups.

If you're going to get a cosworth gasket or cometic or any MLS gasket, you have to make sure that your head and block have the right surface roughness constant. For example, I think cometic requires an RA (roughness average) of 50. Contact cosworth and see what they say.

Cosworth will definitely be a stronger headgasket, but don't overlook the felpro. People have used it for up to 600hp. I personally wouldn't use it for a 600hp KA, but for 400hp, maybe.

One person suggested that using a felpro on an application like that will give you some sort of "fuse". If something is going wrong with your tune or the burn or whatever, you'll likely blow the felpro headgasket instead of something else. Not sure of the validity of this argument, but it makes sense.

[samxini]

A lot of people have good things to say about the OEM felpro on their KA-T setups.

If you're going to get a cosworth gasket or cometic or any MLS gasket, you have to make sure that your head and block have the right surface roughness constant. For example, I think cometic requires an RA (roughness average) of 50. Contact cosworth and see what they say.

Cosworth will definitely be a stronger headgasket, but don't overlook the felpro. People have used it for up to 600hp. I personally wouldn't use it for a 600hp KA, but for 400hp, maybe.

One person suggested that using a felpro on an application like that will give you some sort of "fuse". If something is going wrong with your tune or the burn or whatever, you'll likely blow the felpro headgasket instead of something else. Not sure of the validity of this argument, but it makes sense.

I've heard the same thing about the "fuse" idea too. I'll get a hold of Cosworth then. If not, then Felpro it is.

Thanks for the input guys