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................................................................................................................................. He WON this race . That's the checkered...

hope this works

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Can you tell me what's the dif in weight ,between the running POWERHEADS , of a
75 hp 49 in OMC ;and a 90 HP yamaha ? It seems to me that a sport E boat or a mod 50 boat , with a stock 90 yammy...

...........................Cool !...................................,Uh - the "bird"

I am pretty sure that both units has the SAME gear ratio.

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[QUOTE=marchettih2o;108008]THanks for the input and to the PM's I received on great information. I had a few mention, going as far as .100" on the head...I might start at .060 initially. As far as...

[QUOTE=marchettih2o;108008]THanks for the input and to the PM's I received on great information. I had a few mention, going as far as .100" on the head...I might start at .060 initially. As far as...

for the 1975 -3cyl,the hot setup ,while remaining legal for sport e class,was 19 degrees timing (btdc) and main jets .003 leaner than box stock.If you have a very fast &light tunnel hull-try a V-4...

[QUOTE=Mark75H;104695]Its because carbs work by vacuum. If your carb is too big, there will be no vacuum and no fuel mixed with all that air the large hole lets in.

That is what sets the...

It is my opinion that you will get MORE air through the 1" carbs; why? Because you will get higher velocity , therefore more air. And, that's because your motor cant suck air with the same velocity...

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[QUOTE=Arkansas river rat;102179]Can anyone help me find a nose cone to fit my 1980 50hp mercury ? All that i've found is for a bigger case...

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I've removed...

I think there used to be a shop in ore. or washington that welded and otherwise re- machined
crank shafts , maybe someone out there in "Boat Racing Facts " land can provide the name &address of said...

[QUOTE=Aeroliner;100735]Thanks all for the dyno info. It gives a lot of options to start to investigate. My ides would be to run the selected powerheads on a fixed stand with tower bolt patterns for...

[QUOTE=Aeroliner;100695]As we work to refine our MOD engines it is becomming apparent that a dyno might be useful for development work. I would like to be able to run everything from my A MOD...

My buddy- "MercMack" had about same problem with Boyeson reeds for his 3 cylinder merc 700. He called Boyeson and they did exchange the reeds to the correct reeds . again; the part # on package was...

[QUOTE=88workcar;98321]Just in reading it seems that the comparable evenrude would be the 60sst, when did it come out and how did it fair against the 650xs?...................................

How fast did it go on THIS run ?

You might think I didn't like Chryslers- ? I did like them , I had a 3 cylinder 70 horse on a pontoon boat . REAL good motor . They just had lousy lower units. (performance wise ).I happen to think,...

Chrysler had no motor suitable for "G" it would not be allowed in that class ,anyway, because the motor was a 3 cylinder w/72.39 cu. in. Making it eligible for "H" class. The 4 cylinder had 96.55...

[QUOTE=Roy Hodges;96564]Back in the day, (1975) Tom Ireland ,after much trial &error, came up with optimum settings for the 75 (short shaft ) in closed course competition. 1 step leaner jets & 3...

Back in the day, (1975) Tom Ireland ,after much trial &error, came up with optimum settings for the 75 (short shaft ) in closed course competition. 1 step leaner jets & 3 MORE degrees timing ;19...

So.... keep the engine alive ,with mandatory REV Limiters. Not the kind that shuts down the engine,but, one that just misfires until the rpm's drop to an acceptable rpm.

I watched a few heats on SATURDAY. I have passed by the lake literally HUNDREDS of times in the past, on my way to Oroville(visiting my late wife's family) ; had never attended a RACE there . What a...

Something that I THINK nobody has mentioned ; the rotary engines (omc race) must have been incredibly smooth running , I would think . Any comments from any of you drivers who raced ,using the rotary...

Also; I didn't have to figure anything out ..... because I copied the NYDAHL bars that belonged to a friend , and just left them flat,instead of copying the bends.

I didn't have power trim on my boat? (!) So, it was no problem . That does not solve your
problem ,though.

[QUOTE=Riverrat001;93376]Thanks. I had another set built out of 1/4" plate it's not aircraft aluminum though and I have a 59ci merc on my boat not an omc.........................................

iT SEEMS TO ME that the Detroit river is SO darn dangerous, I wouldn't want to race any boat smaller than,say, a P T boat . Didn't 2 unlimited drivers lose their life on the same day, many years ago...

I forgot to mention; from the top of the transom to the bottom of the tunnel, the height (was) on my boat 24"-that's what it needs to run free- no drag from the gearcase.For TOP speed- about 24-25"...

[QUOTE=Riverrat001;90635]Can someone tell me the approximate prop shaft height to start
trying for an sst 60 for a river toy. I don't intend on racing except for fun................................

Que Paso, Hombre ?

i SAW A NITROUS SETUP BEING USED AT A RACE 'BOUT 30 YEAR AGO,AT FOLSOM (NEAR SACRAMENTO) ON RICH GRUBERS' SPORT E tunnel. It was sent out here to Paul Bender , from the OMC factory. It was only good...

[QUOTE=MN1;84632]Would this type of gearcase have been used in the 36 class?...

I think he's asking about the gear shift units , like those on the 70.7 cube 60 horse v-4 and 90 cube v-4 (75 horse) from 1960-68, before the prop -exhaust units came out . You know, the pointed nose...

I thought aluminum comes from Bauxite ore -the most common on earth, but expensive to
process (uses MUCH electrical power ) and magnesium is extracted from SALT water.

It might help ....if you say which brand of motor you have in mind .

will there be a part 4 ? or has the 4 rotor racing powerhead story been told , completely , already ? This is SO fascinating to me . it seems to me that , w/turbocharging a 4 rotor could put out over...

[QUOTE=Fast Fred;74637]thanks David_L6, the tuna specs change for the SLT, but thats cool, guna take some measurements, i don't want to short change it out of any drive...

I was there,to watch on Sat. did not keep track of who did what, but .............the temperature was actually CIVILISED ! usually, it's about 105 -110 . A furnace !...........I doubt THAT will...

Flywheel, to make sure the magnets have NO rust on em. A little can ruin the spark. sand them clean, if necessary . Sometimes we forget this.

just waiting on the Aussie dollar to get stronger so its cheaper for me to buy the parts from the States!...

I think it meant " 300 ".

I meant use old engines , even with the horsepower (NOT cubic inch) classes. New engines cost too much . No matter what some say , money is paramount. If race rigs were
free ,or say under $500...

[QUOTE=Mark Poole;71764]Brand warfare is what made boat racing so great "in the day". The manufacturers don't want to go head to head on the race course anymore especially with stock motors. Mod-VP...