Would like some input here. If I drop a pair of 575 or 600 horsepower motors in Outlaw what do you guys think I would realistically see for speed?

77-79 MPH

Is that all??????????????? I'm getting 68, sometimes 70 now with twin 454 mags....

I was thinking more like low mid 80's. If I'm gonna just get 77/79, that isn't worth the cost.

I think WAGS382 is pretty accurate in his estimate. I ran an '89 311 with 645 H.P./side right at 80 mph. This was with unlabbed 28 bravos @ 5000 rpm so these motors were not dialed in to peak torque/hp ... I didn't want to run them that hard. Consider that while very solid and predictable, the 311 hull is heavy and "old" technology. Although my '99 382 weighs 3000# more than the 311, it runs almost 5 mph faster with the same motors and props @ 5400 rpm. If your boat is in good condition, it may still be worth the $$$ ... there are not to many 80 mph 311's out there and the Cig guys just crap their pants when you go by them!

Outlaw,

Just saw you are in Sarasota. With labbed props and salt water, you might get a click or two over 80. Let us know what you decide!

If your boat is in good condition, it may still be worth the $$$ ... there are not to many 80 mph 311's out there and the Cig guys just crap their pants when you go by them! [/B][/QUOTE]

That in itself would be worth the money. I'm planning on dropping the silent thunder box and going with an extreme marine tubular platform (if my wife absolutely makes me)(I like the clean look on the back). I know Chief Engines dropped a couple of 750's in a 311 but was never able to get any info on it. I'm planning on talking to Innovation Marine about this, but am also up for suggestions. The boat is in GREAT shape for it's age. I spent a year looking before I grabbed this one.
The original asking price was 47,500 (Nov. 2000) with tailer, and I got it for $ 33,500 then the guy allowed me 3500.00 for my wife's sixteen foot center console fish boat, so I traded that and 30K even. The interior is a solid 9, the exterior a solid 8.5. I'd love to have a Top Gun someday, but that is in the future. For now I'd like to play with this.

There is nothing better than smoking a cig.

I've heard good things about Innovation, but I went with Sterling. They are only one hour from me and are great guys to work with. I know they often ship by truck back and forth to TNT. It would be worth your time to call Mike ... they are not really as expensive as one would think.

I added extra flanges on my platform to lower the water level and also cut out (2) 2" holes in each baffle to reduce any restriction. It sounded wicked but not too loud or annoying. There is another 311 in Monroe, Mich that has a tubular platform on it. It looks good, but without some form of muffling device, I would be worried about noise regulations in the future. The motors you are considering will have a pretty radical sound that you may find overwhelming after awhile, and they will definately attract the attention of enforcement officials.

Red Dog, what exactly do you mean that you added flanged to lower the water level? On my silent thunder, I took those circular holes on the bottom of the box and enlarged them to big honkin' rectangular holes. I worry sometimes if a pelican might try to make a nest up there. I cut the partitions in front of the rectangular exhaust outlets completely out. Made a nice difference in sound and gained 300 rpms on the top end to boot. When the boat comes up on plane and those rectangular holes come up out of the water the noise level increases but not overhwelmingly. Here on the Gulf Coast, we don't get hassled by noise regulations. The VAST majority of performance boats do not run any type of mufflers or silencing systems. I just have never particularly liked the look of integrated/bolt on swim platforms. I just don't like them. I like the clean look like the back of a Cig. I can tolerate the tubular look, because it does not overwhelm. Any feedback on staying with natural aspiration or going supercharged. My gut feeling is staying natural but I am up for suggestions. Some have told me it might ultimately be cheaper just to throw on a set of "chargers" but REALIBILITY is the key ingredient here. Any feedback appreciated.

I raised the location of the stock flanges on the back(stern) of the platform and squeezed in a second set of flanges below them. Basically doubled up the outlet flanges on the tail end of the platform. I kept the plugs in the drain holes to keep a little cooling water in the platform so the fiberglass didn't melt from the heat of the exhaust. It seems that your approach was also very effective in improving performance.

Superchargers are really cool and there is nothing like the blower whine when they spool up. But a good engine builder can obtain very big, very reliable H.P. with natural aspiration. My 510 c.i. Sterlings put out 645 H.P. and over 600 ft/lbs torque with a single carb and a flat tappet cam. Those numbers can be increased to ~675 H.P. with a cam change and the new Crower hydraulic rollers which oil the roller wheels for better longevity and durability than the non-oiled lifters. These numbers would push a 311 to mid 80's and a stepped 382 to about 90 m.p.h. if propped right! That is turn key, no maintenance, and idle very smooth @ 500 r.p.m. in gear.

After two years of nightmares with expensive fuel injection that never worked right, I learned the KISS approach ... keep it simple stupid!

What exhaust are you running? If you are running the Merc cast iron exhaust, you will need to upgrade if you want to optimize engine upgrades. The higher through-hull outlets from the silent thunder platform present some problems which I can caution you about and enlighten you with before you encounter the same.