The motor runs great, 190 hrs all original. It runs cool. My question is, should there be equal amounts of water flowing out of each exhaust pipe? The starboard pipe pumps 25% more water than the port side. Like I said, the boat runs great and doesn't overheat at all.

Thanks

PS
Yes I am easy on and off of the throttle.

My boat has been that way for years. I cant explain why but it hasnt been an issue.

my minx is similar, but if I run it at 1000 RPM's I get a pretty even spray from both.

If you are at all concerned about it, check the manifolds. They rust from the inside out and will cause major damage if they get blocked.

And, if they wind up being a problem, I have a set of GIL manifolds and dry exhaust pipes custom welded for an '87 22 classic for sale. They require no extra drilling of holes and you won't have a problem with rusting again

Do I remove the plate on the top of the manifold to check for rust?

Let us know what you find. I have the same setup on an '87 Formula 242, but I haven't run it yet and I'll be on the lookout as well.

Are you running a drive shower on that Alpha?

I had twin 454 w/ Alpha's. My cooling system had a T apparatus that was above the recirc water pump. At each end of the T was a ball and spring system on a single shaft. It was like an equalizer. However, if one of the balls or one of the springs became worn, then more water would head that direction. However, this T is only for cooling the manifolds and not for the engine. So, I didn't have adverse issues. If you pop the hose off at the T, you will see the ball / spring system (on my old set up anyway).

Regarding the drive shower, I ran twin big blocks against the Alpha's and never had a failure without running drive showers. The Alpha has an internal water pump / impeller. I had to run ear muffs on teh Alpha even though I had under boat engine water pick ups when I flushed the motors. Don't run an Alpha without water going through them.

I do not have a drive shower on the alpha.

By the way, my title says that the boat has 290 horsepower. Do any of you know if the motor is underrated or if they actually only have 290 hp out of the 1987 454 mags?

The 1987 454 was listed as 330 hp. Later versions became 365 hp. Maybe the 290 hp is considered propshaft power for insurance purposes.

That is what I was thinking. They used to way under rate the horsepower on muscle cars for the same reason. Ex: Boss 302 rated at 290 hp! Yeah right!