looks like the higher the numbers merc can post,,the more they will chrge for the engine

If it's clear that the advertised hp is at the crank then they are underrated!

Old thread, I know, but good winter reading.

Must be really bored to revive this thread. But I do have some more data I can share. Most dyno shops including myself use a "standard" correction factor for testing. OEM use an "SAE" correction factor which is a couple of percent more conservative. So the HP comparisons everyone sees is more a difference of testing methods than of actual power produced. I recently rebuilt a couple of 525's. I dyno'd them before tear down and made 556 hp running all accessories and wet exhaust, using the Standard correction factor. I rebuilt them, did a mild bowl blend and used the small dome 502 pistons which added a couple of tenths more compression. With a recal of the ECU we made 581 HP. We also replaced the cam (because of damage) with Comps 525 replacement version. It appears to be a tiny bit milder than the Crane OEM cam.

Bob

Glad you did

still 87 octane or?

The compression is about 9.2:1 ....


I DO fill up with premium on land but would top off with mid grade on the water if I had to ...


Doug