O-ring block/head gasket question

I had my iron block O-ringed and heads have receiver grooves. Question, what bore head gasket do I need to get? Bore is 4.50 and I need a .070 thick copper gasket. Thanks, Chris

 

Measure across the cylinder chamber, then measure the receiver
groove the same way,from one side across the chamber to the other side to the receiver groove,
and compare the measurements, this difference between the two measurements will be the area you have to work with.
when running a thicker gasket the on the shelf availability is usually limited bore sizes,
you just want to make sure you have enough room between the chamber and the oring for sealing,
but your probly looking at a 4.580 to 4.630. Unless you custom order your gasket threw Clark or Hussy ,then you could just order a gasket that is like
.010 to .020 larger than your combustion chamber

Hope this helps

 

head gasket

Clark will make you anything... usualy he makes them .020 biger then the bore.