Can I use 86mm Cometic HG on Stock bore engine?

[OB1]

I understand you can go slighly bigger than you cylinder bore size. IS 86mm HG ok to be used on a 85mm stock bore?

 

[steel_3d]

I would say it would be fine.

Even the stock gasket works with an 86mm bore (just barely, I hope it won't burn on me ). If you measured the actual diameter, you'd get ~86mm on the stock gasket too, maybe that's the measurement cometic is using?

The only reason I wouldn't go too big, like 87mm+, is first that there's less gasket between the bores and easier to blow out, and second your engine might be more prone to knock with the spent gases getting stuck in that gap left by the gasket.

 

[talon94eagle]

You can use any head gasket that has the same or larger bore as the block even if it's 2mm larger it won't matter you'll be fine.