B20 head cc?

[mobebk]

Im finishing up my project and puttin it in the shop this weekend for the machine work (3 angle, hot tank, bore, cross hatch hone, micropolish the crank, etc).
I was wondering what type of head gasket I should use and if I should open up the head chamber.

The setup
Wiseco 84.5mm pistons 11.1 comp
eagle H beam rods
ACL bearings
RS machine resleeved block
crower 404 cams
crower springs and retainers
gsr oil and water pump
many more

The head is at 81 mm and the stock head gasket for B20s I was told are at 81.5mm. Why is that. Why wouldnt the head be at 84 also
help me out here please, and what type of gasket would you recommend. The comp is at 11.1 with a 3 layer. I will also be shooting an 80 shot direct port
thanks in advance

[CRVTEC0WNZJ00]

My 2000 ITR cylinder head was bored out to match the 84.5mm bore of my B20Z sleeves, I'm using a Cometic 84.5mm head gasket, basically if you have the combustion chambers bored out to match the cylinder bore you'll gain some displacement but doing so your compression ratio will probably drop down from 11:1:1 to around 10:8:1 but thats just a total guess on the compression ratio, there is no real need to bore out the combustion chambers to match, I just believe they should match just like OEM is supposed to.

[mobebk]

yeah im thinking of doing the same and mathing the head out to 84.5 mm also. i just dont think its a good idea for some reason the head chamber not matching the bore. maybe mixing, more stress on the head, i dunno.
The b20 head is actually a b18 ls head, thats why im confused about what to do with the head chamber.
thanks for the help

[CRVTEC0WNZJ00]

You're welcome, I just think it will improve flow to some degree, ITR206 doesn't think that but Rev Atari thinks that and obviously my engine builder a guy who built Honda IRL engines and shit thinks its a good idea too, so I'd do it personally.