loop
You do not say what engine or prop but assuming a four cyl Lyc, you just can't hardly hurt these engines. I operated the A4A in my Pitts for 1000 hours at 3300-3500 rpm almost every flight. The exception was cross country at 2500 to 2750 r/m. Your LIKELY problem with the loop is not that you didn't pull hard enough, but rather that you did not "float" the top enough. The entry and exit COULD be done at 2.5 G's, although 3 would be better. To dispel the "clean airplane" nonsense, I did a lot of loops in the Glasair I, 0 320, fixed pitch metal prop, no inverted system. The goal is to come as close as practical to zero g at the very top without causing a power interuption. With the Glasair if I did the loop properly with entry speed of 180, exit speed was 180, full power all the way around. If you are fairly new to this, as you approach the vertical down, if you sense you are going too fast, by all means pull the power back, all the way to idle if necessary. The ultimate goal is full power all the way around, entry and exit speed within a few knots. I met a gentleman years ago who had split s'ed a RV6 at near 300.
I would not worry about the speed you reached, just try not to do it again. Be VERY AGRESSIVE about pulling the power back if necessary. If you have not had some formal aerobatic training now would be a good time.