Compression is dependent on head chamber volume, gasket thickness, piston notch/dome, compression height, and deck height/deck clearance.

Doug, I presume you did not reassemble your engine using factory metal shim gaskets...FelPro and other composite gaskets are thicker. Did you replace your pistons? What was the compression height? What volume were the valve reliefs? What did the chambers cc to?

This is just to illustrate that you can't order "10:1 pistons" and get 10:1 actual compression. There are a lot of variables. With your engine, Doug, I have two sets of heads in my garage that would drop your compression to 9:1 or 7.8:1 without any other changes. But if yours does measure out to 10:1, that .25 drop from my compression might be enough for the additive to be effective. Next fillup I will put a bottle and a half in and see if it helps. If not, I'll dump in the rest of the bottle.

Padded numbers, whether for horsepower, torque, or compression, was a marketing gimmick of the day. No one stretches claims any more, do they?

I'm in the first stages of building a lower compression engine. That will fix my fuel issues.