A 26p is a pretty big wheel to spin. I know a lot of 272 folks have trouble spinning a 25p with anything under ~625 HP.

My 272 would only spin a 26 non labbed 5200 at 72/73 with 645 ish gross dyno hp, needed a 26 labbed. A customer has a aetco 580hp 540 in s single checkmate, wont even turn a 26 LABBED past 4800, fwiw, your dead on. A modded 500 efi unless its super strong and in a light, stepped hull ) like a 27 fountain isnt doing it either. Fwiw, Smitty

Some boats (Like Formula) use 1.65 gears. Thus why bigger props than others of the same size.

But yeh, my experience for most , say, 26-30 boats with 1,5 gears end up with around 24 Bravos with 500-550hp or some more. That's why used 24 Bravo's don't stay for sale long. Very popular prop and size.

My 272 Islander with about 500 Dyno HP spins a labbed Mirage plus 25p with 1:65 gears up to an indicated 5600 and 64 mph. Even if he has 1:65 gears 26p is huge.

I didn't know about the graduated timing steps. If it can't spin high enough to advance the timing then that's certainly problematic.

Stock 500 efi timing table is a joke, its at 27 or 28 degrees thru 4800 then jumps to 35.9 suddenly in 200 rpms (at a 100 map)