Re: How much power would it take to make a 28 cig run 80mph?
 

Follow up question. How would I come up with the ultimate x dimension for this boat if I want to keep the trs drives?

Re: How much power would it take to make a 28 cig run 80mph?
 

Mandatory: hydraulic helm and external steering. That made the boat handle a ton better, reduced chine walk considerably. In dead falt water it wanted to chine walk at 80 mph, but at 84-86 thew chine dance went away and it wanted to porpoise a bit in dead flat water, but the porpoise was no big deal, you wanted that in order to break the bottom loose and reduce wetted surface area. Once we crossed some boat wakes, or waves in the Ocean the porpoising stopped and the bottom worked great. We raced alot boats in the ocean off Margate and Atlantic City in the first 10 to 15 years of ownership, the boat handled great, that big-block stuff is BS regarding handling at varied water conditions at 85 mph the boat flew level, we smoked the small blocks - 28' SS's, period, in any water, not even close, but with todays stroker small blocks, and the fact that you have a set of them stick with the sbc. I like the Bill Mitchell small block crate motors, if repowering is an option, though I do not have first hand experience with them. My father had big-blocks, and bought his Magnum without power. We looked to get into at least one race, on most days two or three over the course of 19 years with 12+ weekends of boating per season we raced alot of people (some repeat runs against the same boats), the point is I had the seat time, and my father more so than me had the seat time (it was his boat), so I am not blowing smoke up your @ss. That 28 SS will need to be driven, and need seat time to get comfortable with it. There was a 28 SS with 475 hp motors (on the dyno with tube headers, P-1000 exhauts in the boat),it did not run 80 mph (if on same radar gun that radared us at 81 in the early 90's - the Barnegat Bay radar shoot-out), but he did not have it all sorted out. If you get it all sorted out (props, bottom, ect) the boat will be alot of fun, but you will need to learn how to drive it, it is not a point, trim and go boat, like some of these boats today. We have a 34' Phantom now, and now I realize the newer design step bottom boats of today (with a semi-pad), handle nothing like that straight-V I had been in for so many years.

Drive height, take it to the rub-rail or higher with the TRS drives, what centers are the motors? Our Magnum had 32" centers, which killed us for an aftermarket exhaust system that would fit, have tube length and not be restrictive. Small-blocks should not have the same issue, that we had. If you go Bravo, the are a shorter leg compared to a TRS, I have no advice on X-dimension, with a Bravo set-up.

The 28 SS was my favorite boat when I was a kid, and the 27' Magnum was right there too. It will just take time and money to get that boat to run 80 mph.

If you questions with set-up/technical, and handling speak with my father - Alan Jones: 856-589-1070, he is much more techically (engine and drive expertise) proficient than me.

Re: How much power would it take to make a 28 cig run 80mph?
 

The bottom work is not a big deal. My experience has been that you just need remove any hook and lengthen the inner strakes, maybe 6-12" past the CG. You can then go back and remove some length if you want more bow lift. The bottom work is only a few thousand...a drop in the bucket compared to the re-rig, engine build, drives, hatches, steering, etc.

Re: How much power would it take to make a 28 cig run 80mph?
 

Check out :
http://www.go-fast.com/boat_speed_predictions.htm

If you know what you have now, this calculator will do a good job of telling you what you'll need. Since it bases the final calc off what you have now, everything should already be taken into account (hual design, x-dim, etc.)

I've been playing with this based on a bunch of dyno tested buildups and it's seems amazingly spot on as long as you have a baseline.

The site also has a calculator for prop selection. I ran a bunch of similar boats with different props through this and it seemed to work out well.

Re: How much power would it take to make a 28 cig run 80mph?
 

keep the TRS transom assy, put konrad shorties on, that will raise the X as well as build reliability. build a lil more power and you will see 80. its not to tough to ring it out of a cig.
its even easier on a lighter hull.

Re: How much power would it take to make a 28 cig run 80mph?
 

A buddy of mine has a 1976 28ss with true 400HP (dyno'd) engines. it has the mercII trannies and TRS drives.....on its best day we hit 67mph on lake michigan...he has hit 70 in the ocean in Miami once....the boat has not been modified hull wise at all since it came from the factory....so the setup is not "dialed in"
And i've personally seen a 28ss that had 500efi's with prochargers and extension box's and the owner said the engines were doing 650hp ea and the boat was in the low 90's!

Re: How much power would it take to make a 28 cig run 80mph?
 

One of my boats is a 1973 magnum sport-2 years ago it had 11 1/2 to 1 small blocks with merc trans 2 and trs-the x height on the trs was into the rub rail-after blowin up numerous transmissions I had rerigged with 406 bravos-standard x height on a bravo ( and I am going off of memory)is approx somewhere around 14 1/2 ".I set my x height to 18 inches with my 406 small blocks and it runs well over 80 all day long-needless to say I need 4 blade props to get it goin-those motors are for sale if you want them-just put together some dart 434 small blocks.cause im feelin the need for more speed.never had a problem with trs however if you are puttin a boat together with those merc trans 2 trannies your crazy-parts are hard to get and if you build a big small block it probably wont have alot of vacuum at idle because of the cam and if you shift those trannies over about 600 rpm's they wont take it FOR LONG

Cig 28 that was here on the chesapeake ran 75 with 450hp small blocks, trans?? and stock TRS setup. It went up for sale maybe two years ago, and is now ???? First Cigarette I ever saw that had separations of webbing/stringers to hull issues - must have been run guden hard!!:)

Hello J-Bonz,

Who's Exhaust Manifolds are on that 28 SS?

Thank you

Jim