For all who want to know here are all the heads that u will encounter. Not including the VVL motors and Roller rocker motors. I will include the rest when I get some more time.
58Y SR18DE JDM highport.
64J SR18DE JDM lowport.
94Y SR20DE US lowport.
53J SR20DE US highport.
89J SR20DE UK lowport.
96J SR20DE UK highport.
53C SR20DE JDM Pulsar GTIR.

A few months ago you posted this. I was wondering if you could post the rest of the codes.

A JDM motor a friend just got has 53J stamped on it. . .does that just mean that this JDM is a 9.5:1 since it has the same head as the US?

BuMp!

Andreas also posted in that thread:
SORRY GUYS THE 53J IS US AND JDM.

This head 53J will be found on all highport motors US, JDM and Blue Bird Turbo motors. The BB motor being diffrent with SODIUM filled valves that have a 7mm stem verses a non turbo head that has a standard 6mm valve stem.

Also (I may be wrong here but...) IIRC you cannot tell from the head what compression of the motor is.
The turbo motors are lower compression than NA motors, correct? But all those engines use the same head code, and I am not certain that the different valves have anything to do with compression. (one again I maybe wrong on that)
But one thing I am certain of is that the pistons are what you need to be concered with more than the head code. Anyway I hope this help you in some way.

so the lowport is on the b14 right?

Yes, B14 is most certainly lowport. :)

I never know they have other codes for the engline