I love the idea of a 671, but they seem out of my price league. And how much taller than a 250 are they? I won't cut my hatch.

Quite a bit taller. The 250 is low profile though. And would be my choice over the 177 like the guys here said

That's why I was saying the 250 over the 177. I know not much of a gain. but better. the 671 is another large upgrade cost and height wise.

Here is an old picture of my former Top Gun when I had the Chiefs. They were 671s but they were tall.

Yes, I was going to put them in the swap shop this week.

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How much did those coolers bring your oil temps down?

Hey wayne, what would you say the cam upgrade and 177 install gained you over the stock 454s in the bullet ?

To be honest I was running I was running 2"x4" power steering coolers on my original Merc 420's. No temperature gauges. When I re-powered to ~600HP engines I put the 3"x18" on. I have never seen temps over 180*F after the cooler delivering the oil to my bearings and I run over 5500 RPM's for miles.

Would putting a 250 blower on a GenV block with forged internals, aluminum heads, and 9.5:1 compression be too much? I'm just conceptually asking here as I plan out my motor. Or would you pull the pistons and lower the CR ratio?

Hey guys,
I'm new to the forum and this is my first post. I cant seem to start my own discussion but This one seems somewhat comparable to what I'm doing. I have a 1989 Formula 242 LS. The boat originally had the 454 magnum (365) with GIL exhaust on it. I pulled the motor this season and had it completely rebuilt. I threw a Cam in it, punched it out 30 ,,new DART heads, bigger carb ,new exhaust ,,the whole deal. It came off the dyno making 526HP with 558 ft/lb of torque.
My question for anyone out there is what I should be looking at for a prop. I had a 21 pitch Mirage plus with the original block and it ran perfect...58 mph-61mph on a good day. My motor at peak performance now turns at 5300 RPM. I have plans to change my prop but I'm wondering if a 23 mirage plus 3 blade may be a bit small. Should I be looking at a 25 pitch Mirage plus?
I'm told these old formulas like the 3 blades, but any information would be helpful.
Thanks

The 25p Mirage+ is a monster to spin. Many folks use a Mirage+ 23p and have it tuned with a bit more cup to a 24p. But to get you in the ballpark BBlades rents props for trying out for $50. You can rent the 25p and if the motor or boat struggles with it then find a 23p and have it tuned.