Here's the spec of my P8R and B20 block from C-speed calculator

P8R Combustion Chamber 47cc
B20B4 84.5mm x 89mm
will be using 3-piece Headgasket

Now I have the following options to choose and they have the following dome size specs. My concerns is their piston-to-valve clearance with my 404 cams @_@" make me scare there is p2v contact

These pistons will yield lower C/R than their factory states because of the larger combustion chamber ( 47cc) in P8R head

RS machine pistons
Bore: 84.5mm
dome size: 1.3cc
C/R: 10.22 : 1

Probe SRS pistons: 11377-3.5 (Low Dome)
Bore: 84.5mm
Dome size: 3.5cc
C/R: 10.6

Probe SRS Pistons: 11377-3.5 (High Dome)
Bore: 84.5mm
Dome size: 7.1cc
C/R: 11.33

I've also consider Spark Racing Pistons, but I do not have the specs

My first priority would be of course the high dome (yields 11.33 : 1) because of the 404 cams. If there is p2v issue, I will size to lower C/R to the one next to it.

Anyone doing B20 P8R non-vtec power, please post what pistons and what cams you are using.

Thank you

 

Hey hey. Im just closing my motor and will open a new post wen will be dynoed.
but to help u. i use custom pistons cause my motor will be VTEC nex year
But my pistons are VTEC piston that are usualy made ready for big vtec cams ( 12.5mm lift 315 deg.)
i use flat top pistons wit 4cc notch (-4cc) that made 11.3:1CR (wit P8R head Shaved .020) on my 84.5 X 97mm B20
Wit .240" clearance using TODA B cams in GSR head VTEC engage
Check out the CR number that compagnie tel u. never thrust anny
make your mesurement and check your clearance
My P8R head is a real munster flow. at mid lift of B18b cams (.200) flowing 20CFM more than Si-R stock one.
Using stock honda P8R valves no valves job but ported III by myself
using Si-R P-30 IM to fead it

 

If the torque number are good, nex year ill be going wit Crower 62403-2
My GSR Vtec head can wait ! lol