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Discussion Starter #1 (Edited)
I am running a 468 bbc with 560 lift, log exhaust and 781 heads, air gap intake, 12jc "A" impeller. I have a 3310 750 vac carb ready to go, would that be the best combo or move up to mech second 750 double pump, or 850? I remember someone saying on here there are minimal gains between the 3, I am building a nice cruiser with some balls..steel crank, upgraded rods and valve train. Also what opinions does everyone have on marine carbs, starters, dizzy, fuel pumps versus auto, I am running an open engine. Thx for reading!
 

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Ok, I'll take a shot. If you already have a good 750 with vacuum secondaries, I'd run it. If You have access to either a 750 or 850 with mechanical secondaries and it wouldn't cost you anything to change, I'd run the mechanical over a vacuum carb on a boat. I wouldn't spend a bunch of money to change your good working carb just to get rid of the vacuum secondaries though.

As far as "marine" alt, starter, fuel pump, they are a good idea. Again, I wouldn't throw away any good parts just because they are not "marine" as long as you have an open engine compartment. If your engine is closed then I would definitely recommend marine for both safety as well as liability issues. What makes these electrical parts "marine" is they shield the armature so it can't spark and ignite any fuel fumes that could settle in the bilge. The fuel pump will have an extra vent tube that would vent through a clear line to the spark arrestor or air cleaner allowing you to see raw fuel in the line if the diaphragm started leaking.

If for some reason you had an engine explosion do to fumes being ignited, your ass would be in hot water if they find you don't have marine rated electrical components on your engine, but this is usually only a problem with closed engines. Hope this helps.
 

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Discussion Starter #4
I was thinking the same thing. I do have access to other carbs and I am going to break the motor in on the dyno so i will swap them and see since I'm paying for the time anyways. Just wanted to see if I was on the right track. I'm not too worried since fumes wont build up but I'm not ruling out anything yet. Thx again!
 

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ok, i'll take a shot. If you already have a good 750 with vacuum secondaries, i'd run it. If you have access to either a 750 or 850 with mechanical secondaries and it wouldn't cost you anything to change, i'd run the mechanical over a vacuum carb on a boat. I wouldn't spend a bunch of money to change your good working carb just to get rid of the vacuum secondaries though.

As far as "marine" alt, starter, fuel pump, they are a good idea. Again, i wouldn't throw away any good parts just because they are not "marine" as long as you have an open engine compartment. If your engine is closed then i would definitely recommend marine for both safety as well as liability issues. What makes these electrical parts "marine" is they shield the armature so it can't spark and ignite any fuel fumes that could settle in the bilge. The fuel pump will have an extra vent tube that would vent through a clear line to the spark arrestor or air cleaner allowing you to see raw fuel in the line if the diaphragm started leaking.

If for some reason you had an engine explosion do to fumes being ignited, your ass would be in hot water if they find you don't have marine rated electrical components on your engine, but this is usually only a problem with closed engines. Hope this helps.
x 3
 

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Discussion Starter #6
:))THumbsUp:))THumbsUp:))THumbsUp

Another question, anyone know the hardware required to bolt/attach my Berkley intake to my hull? And the hardware for intake to pump? thx
 

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hey Mike ,Don here . are you dealing with jimmy richmond ? if so whats he think? I have an 850 dp you are welcome to take to the dyno. cheers
 

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Discussion Starter #8
Yo Don, no I just got it done myself all the machining was already done so I just had it put together with a buddy, but I talked to a few people about the cam and other key things which needed attention. Thx I will take you up on borrowing that carb!
 

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Intake install

Its not as simple of as your thinking to just bolt an intake in. Do a search on the boards on how to sit an intake. Or call Tom of Jet Boat Performance for guidance or have a pro do it local to you.
 

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I'd go with the 750DP is you have it handy as well. I have a 'cruiser that's stroked with a .570 lift cam. I run a 750DP. I just play around on the lake with it since it's the family boat, so I'm not that worried.
 

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Discussion Starter #12
Its not as simple of as your thinking to just bolt an intake in. Do a search on the boards on how to sit an intake. Or call Tom of Jet Boat Performance for guidance or have a pro do it local to you.
Ok thx Blue I will call around on that one. But as the intake was already on the boat from stock what is my main concern? I haven't changed anything I just wanted to put new nuts and bolts. Am I missing something? :)eh:)
 

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You will notice on the corners of the intake threaded holes. These are for leveling bolts for setting the correct height front and rear in relationship to the bottom of the hull. Also correct measurements from the strakes so its centered. Can't be crooked or to deep or you will have problems. You also need to use Marine Poxy Puddy when setting it in. From the last picture, you pulled the intake out. If the previous holes are still there you can get away with re-using but I would measure to make sure it was centered from before. You will also have a problem with the height for the leveling bolts since the holes in the hull have already been drilled. Best to fill the holes to drill out after setting the intake.

Not an expert like others here on the boards, but know it is very important when going at high speed.
 

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Discussion Starter #15
You will notice on the corners of the intake threaded holes. These are for leveling bolts for setting the correct height front and rear in relationship to the bottom of the hull. Also correct measurements from the strakes so its centered. Can't be crooked or to deep or you will have problems. You also need to use Marine Poxy Puddy when setting it in. From the last picture, you pulled the intake out. If the previous holes are still there you can get away with re-using but I would measure to make sure it was centered from before.
Ok I see, I pulled the intake out because whoever installed it originally wayy before me had used so much blue silicone and crap it leaked bad so I pulled it and had a fiberglass repair shop fit the hull to the intake, did not change any of the holes. So other than it being centered what am I shooting for on depth? I see the threaded holes on the intake.
 

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Ok I see, I pulled the intake out because whoever installed it originally wayy before me had used so much blue silicone and crap it leaked bad so I pulled it and had a fiberglass repair shop fit the hull to the intake, did not change any of the holes. So other than it being centered what am I shooting for on depth? I see the threaded holes on the intake.
Best to fill the corner holes in the hull so you can use the bolts for depth and leveling and drill out later. Also, even though you have previous holes, you need to measure from the strakes underneath so the intake isn't crooked. Needs to be level from side to side also. Depth is set in relationship with hull underneath.

I'm no expert like some of the guys on the boards here, but it has to be done right especially if you are running at high speeds.

Talk to an expert.
 

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This is one area that doesn't need to be scrimped on! Setting the intake at the right 4 to 5* angle is a factor also!

On the carb! If you are testing on the dyno for break in then for sure try and all the carbs 750 vac.,750 DP, 850 DP! I think you will be suprised with the outcome! And as a rule of thumb if you have to take lets say a 750 and increase the size of jets from stock up to and over 4 sizes step up in carb size! Just my .02
 

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mike have you heard of a guy named Herbie out of mission? I don't know him well,old time jet guy been into jets since the 70's.Don't know if he works on boats on the side.He works at M.R. dodge dealership. Thats the guy locally I'd try to contact for setting intake. I can try to track him down if you would like.
 

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Discussion Starter #20
mike have you heard of a guy named Herbie out of mission? I don't know him well,old time jet guy been into jets since the 70's.Don't know if he works on boats on the side.He works at M.R. dodge dealership. Thats the guy locally I'd try to contact for setting intake. I can try to track him down if you would like.
I'm gonna go to that dodge place and ask someone there. How many guys into jetboats and named Herbie can be working there at any one time??
 
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