oversize head gasket
 

My extra block that has all machine work done is bored .080 oversize. I bought the copper head gasket and it barely fits over the bore of each cylinder. I mean the openings are almost line to line fit if not an exact size as the bore. I haven't installed the pistons to see if they are down in the bore any at all. Should I try to find a different head gasket that has more bore opening?
Ed

Re: oversize head gasket
 

Isn't 0,080 just barely over 1/16th of an inch? So on each side even half of that???

Re: oversize head gasket
 

I forget the part number but the copper gaskets I got (from NAPA) measure 4.125 center to center on the fire ring.
Two of my engines were 4.040 bore. Worked fine with offset bores.

Re: oversize head gasket
 

1/16 of an inch is .062. That would be approximately .030 off of each side. .080 would be .040 off of each side.

Re: oversize head gasket
 

My understanding is that the copper head gasket available now fits up to an 0.125 oversize cylinder bore. Maybe this is not / no longer the case?
The weakness in a big bore gasket is the minimal material between the cylinders. In my opinion, the big bore gasket contributes to the common burn-through between Cylinders 3 & 4.

Re: oversize head gasket
 

That is what I was afraid of. If my pistons extend above the bore, I am thinking of turning a small chamfer on the top edge of each so the piston would not hit the gasket.
Ed

Re: oversize head gasket
 

Best 509G works just fine on my .100 over, and my pistons go above the deck.

Re: oversize head gasket
 

The link to Vince's site shows the bore size of the different gaskets.
https://www.fordgarage.com/pages/ABc...asketguide.htm

Re: oversize head gasket
 

Best composite gasket on mine. .125 over

Re: oversize head gasket
 

My engine is 0.080” over, I use the Best 509G and am very happy with it.