High Compression SOHC CRX

After doing some research on my current set-up. The ZC block and SOHC D16a6 head has a 10.75 CR. I had some problems for a while with the engine running lean under load. I put an adjustable fuel press regulator to fix the problem and it still a little lean at 55 PSI. It does run a lot smoother and more power but I know it could do better with more fuel. My question is how much PSI can the stock injectors and pump tolerate before they have problems ? I am sure I can use bigger injectors but I'm not familiar with sizing. I also have a d16y8 head I'm planning to put on and that will put me between 12.5 and 12.75 CR. If anyone has suggestions on how to tune high compression motors like timing adjustments, fuel delivery or injector upgrades that will help.

Yeah, you could use some new injectors. JC whitney carries em and they even have a formula to find out what ones you need. If you are running lean under load that is a big problem. You could be detonating and doing some major engine damage. I would also definately put in a larger fuel pump that can pump more volume and pressure. As for your timing, if you are going to put on that new head, you will definately need to retard it to prevent detonation. Or you could just run 110 octane ;). Take the car to a shop with a dyno after you install all the parts and get it tuned....this will definately help out.

I wouldn't turn up your regulator anymore, fix it right. at 75 psi your injectors won't even close.
If you're leaning out at top end you may have a lazy o2 sensor, could be the ecu you are using as well.

Actually, I just rewired my a/f gauge to a better ground (at the battery post) and it turns out the ratio is right where it should be. Using a common ground really does make a difference. But just to let you know, D16A pushing 10.75 CR has really good power. Vtec head and NOS coming soon.