Engine Poll
 

OK, polls are fun. Just for fun, if I was going to re-power my 28 what would you guys support. I'd be looking for about 750hp. So, the two options I'm realistically considering are either a Blown 540 or an N/A 632.

What do you think? Pros and cons of each?

Never been much on blowers......they tear down an engine too fast and I ain't got the money for that.

With a blower you don't need as radical of lift and won't beat the hell out of the valve train. A 540 with a blower would be extrememly low on boost and therefore very conservative on the wear and tear of the engine. A 632 on the other hand will require a huge cam and will crush the springs in 100 hours or less.

That's my opinion, but what do I know, I still can't go faster than 87!!!

Kirk, I'm only looking for 85 mph so I figured I could go with a couple hundred less hp! :D

Sorry dude I'm kidding.

I'm wondering how radical the valvetrain would have to be in a monster displacement N/A motor? 100 hour valve springs are a turn off, but once a year isn't terrible...

You Could Go With A 572 C.i Or A 600ci Motor And Be At That 750 Hp With No Problem 632 Is Over Kill More For The 13, 1400 Hp Motors Where The Guys Can Aford A Rebuild Every 50 To 100 Hours :)

Check out Zul's build on his 750.
I know Rick (onesickgladiator) had a pair in his gladiator and loved them.
He was getting 775 out of them.
I'd go NA and carbed... not efi.
http://www.zulracing.com/engines.htm

Stay away from a 632 ci motor, the torque of a 4.750 stroke crank will destroy your drive. I run a 14-71 blower 6 lbs of boost with a mild solid roller cam 672 lift with a Bryant knifed edge 4.375 stroke crank 6.800 oliver rods, 4.600 bore. A 540 blower motor will be ideal to get you to 85+ with no problem.

I've got an Imco upper on the boat but I figured the big crank could be trouble and I've heard that the 632s have some "funny" stuff going on with the stroke in excess of the bore. So maybe I should assume a 598 n/a motor as option 2 (although the blower motor seems more popular at this point).

I think you could bore and stroke your 454 to 496, bolt on a set good heads, and blower to make 750HP.
There are also lots of N/A 572s and 598s making 750+HP.

Personally, I'd bolt in a 600-650HP 540cube and live with 75-80mph. You won't be blowing up Bravo drives monthly.

Again, a 598 ci motor is an over kill for the Bravo as well. It is 4.500 inch stroke which requires beafy heads and a cam that rocks the boat. Get a 540 blower in there and you will be amazed, ask Brian Stubblefield here on the board, he runs 92 mph with it.

I like the milder blower motors. Had a 454 magefi wth whipple in the daytona 25 and now my 540 in the Pantera with a mild 6 lb Whipple system, dyno'd 662 uncorrected in a 99 degree room at 1000 feet of elevation. At cruise you are out of the boost so the motor has a kinder life and mileage is pretty decent, boost is there with a flick of the wrist, sounds good too:)

It might be asier to sell Griff's/your boat and move up a notch:drink:

dude, PM sent.

Tomas, you know something you're not telling us? You voted for NA!

Cattitude, you're a funny guy! You're boat is beautiful. I'm amazed it hasn't sold yet!

Not to add any more confusion but a 3.3 whipple intercooled with a single carb on top of your blower prepped already stout long block would be an easy bolt on and then you could take your time building the 502 or 540 to eventually put under the 3.3. Then return the 454 to a stock 525sc as spare or sell.

I also think that the whipple will fit under the hatch where an 871 needs more height.

Actually a very good idea, mighty not gain much without a cam change though:drink:

I think Griff already did the cam upgrade, hopefully he'll chime in.

And it would be possible to do it all without loosing one weekend of boating.

Yup, Griff did an upgrade to the cam. I was looking at the card yesterday, but don't remember the numbers. Brain fade.

I'm not really into the whipples from a looks perspective and I really don't like the lack of positive drive that the serpentine style belt provides. I'll admit I like the classic big roots blower look and cog belt.

Chris I saw you lost a drive. Sorry to hear that! Man, the season is too short for you not to be out running the boat!

What do you think of the looks of the whipple 305 blower, It resembles the roots more closely and will work nicely on 454 to 598 engines.

More traditional looking and definately a plus that it has cog belt drive. My favorite are those PSI high helix units, sadly my mysterious rich uncle hasn't appeared to give me a bushel basket full of $100 bills yet!

I'm definately leaning towards a roots blown 540. I may stick the roots on the 454 for now and get everything set up and then do the 540 long-block as I get the time.

I've been thinking of buying a used motor, but my stomach knots up to think of shelling out big cash for something (even if its cheaper than building something new) and not knowing what's really inside it.

IF/WHEN you go that way- look at a Whipple with carb- has the traditional looks, much better/more efficient blower

Albert, I was under the impression that Brain Stubb's boat was a big displacement motor. Is it only a 540? And do you know whether he has a full cabin or not?

hey , Sean Hope all is well , sounds like you need two motors not a biger one.

Rocky, you know mine has a loud stereo and a swim step! :D

You should bring it out for the ski race and rum run. Were going to be out both days and doing a big raft up.

Nah, I was going for reliability and perhaps fuel efficiency when I voted for the N/A. I didn't have the drive in consideration, but the 632 is as Albert says probably not too kind on a Bravo, but there are other drives.

Altough a 540 blower is what I would go for, I have always liked blower engines and will hopefully stay with them for a while. :evilb: With 750hp they should be pretty nice and gentle as well and running for many long hours.

Thanks Tomas, I was a bit worried when I saw your vote! Good luck with all the repairs!