Our 30 Mystique project is nearing completion. The 575 SCI's were completely rebuilt by Dorr's Marine Engines in Windham Maine. They were bored to 4.500, a bit more compression with flat top pistons (8.2:1 comp) all new Ferrea valves, hydrualic roller cams by Ultradyne with a grind similar to the HP 500EFI. The stock Weiand 256 blowers were rebuilt by The Blower Shop and ECU's/injectors were recalibrated, rev limiters bumped to 5450.

Yesterday we ran them on the dyno and MAN!!! do these things respond to a decent roller cam selection and a little more compression. We ran about 20 pulls and saw consistantly 680 hp @5400 with a peak of 689.8.

Torque curve was incredible, they're making 650 ft/lbs from 3500 all the way to 5400 with peak torque of 685 @4500.

We were pretty impressed by the numbers achieved WITHOUT spinning the blowers any faster, just the stock pulleys and 4 lbs of boost. This should make for a very reliable combination

Come on SPRING!!!


Kurt

Good job Biggus. I bet that Paul can't wait for some warm weather!!!

Those are awesome numbers for what you have in them Kurt. Congrats---glad you're happy!

Congrats, it should still run around 100mph.

LS JR.

Thanks guys, it's nice to see these results from a very mild but well chosen combination of parts. They idle bettter than a stock 575 SCI and run as smooth as electric motors!

Hey Biggus, I just got the numbers back on my 575's they are about the same as yours.

I can't wait to get this thing in the water.

Nice work by Tim Dorr. I am amazed at the results with low boost and no intercooler. Mercury was too conservative with that engine, selling it with low compression and a flat tappet cam, maybe to save the drive. Say Hi to Paul!