Why do I need an 87mm headgasket?

[Hiitman]

Road Race didn't feel like explaining this to me so I'm hoping somebody on here can. I've got a standard 6bolt bored .020 over (85.5mm right?). RRE told me to get this headgasket EXTREME PSI : Your #1 Source for In Stock Performance Parts - Cometic Phuzion Head Gasket 87mm : Mitsubishi Eclipse 90-99 which has a bore of 87mm. The only reason I can think of is that the headgasket is 87mm before the o-rings are inserted. Can I just use a standard Mitsu MLS?

 

[pneumo]

Yes, .020" is 85.5mm.
Cometic also makes a HG for 86mm bore.
Mitsu MLS is also good for 86mm bore.

 

[Hiitman]

Ok. Still wondering why RRE told me to get an 87.

 

[keltalon]

Ok. Still wondering why RRE told me to get an 87.

Because I think the fuzion gasket only comes in 87mm. Every site that sells them only has 87mm listed!