Advancing/ Retarding Camshaft

I got a 273 that someone before me put a cam in and have low compression(think they
put in the low compression pistions when they rebuilt it) Anyway, couldn't get it to ping
no matter how much I advanced the timing so I took the timing chain off, counted sprockets, figured 1 tooth is about 8 degrees. Advanced the timing by one tooth. The compression is now a little better and it runs better than it did. Verified advance when I put the timing light on it - had to turn timing back about 8 degress. I read somewhere that if you have to advance your timing more than 8 degrees - your cam is too big.
Also read somewhere that if you advance your timing, your basically moving your power
curve also. So if you advance it - if your old power curve started at 4k, it might now be
around 3-3.5k.. In my case, think my cam is too big and I don't want to risk bending valves by advancing any more than 1 tooth.