Long story short, my 303 has a pair of supposedly "warmed up" 454 mags. Externally, however, they look like 425's (Gil manifolds, high rise intake's, etc.) The original owner obviously did some minor mods, but I didn't think he did anything internally.

My boat seems quite fast compared to similar 454 mag boats, but I always chalked it up to the exhaust, BG850 carbs, msd, and labbed props. (74-75 mph gps @ 5300)

After our long trip to key west, I thought I had picked up a load of bad gas. The motors dieseled on me for a second and would not shut down. I idled them for a while with the hatch up to cool them down, and they shut off normally.

My port engine developed a dead miss, replaced caps and rotors (they were pretty well spent) and the miss was better, but not gone.

I decided to do a compression test and the cold readings, carb buterflies closed were:

173
173
175
172
176
182
171
176

Do these seem high? I'm super excited to see i don't have an internal issue, and I like the idea of the higher compression, just seemed a bit off for Mags. Is there a chance I have HP425's?

Engine has 398 Hours.