[tunneljet]

I have a 505 BBC 12.5comp ported dart 310 heads. It currently has comp cam 11-734-9 in it. This is a 110lca, 278in 286ex duration, lift in748 ex714. Is this a decent cam to run in a tunnel hull jet? Also I have a dart dominator intake and I would like to run a 4150 carb, is there an adapter with the cloverleaf pattern to mount my 4150 to the dominator manifold? This is not a race deal just a lake hotrod, so I don't have to have a perfect setup, but would like it to work good. Thanks in advance.

 

[Bruise Brothers Dad]

I take it that the cam is the solid roller. If so you are going to love this cam for hot rodding around. At 4500-5200 it starts breathing fire. It idles nice and semi easy on the valve train. Ran one in a car, I know it's not a boat but a 3300 lbs camaro with a 454 and a 1050 carb ran 9.60's at 145 mph. Soooo hang on and smile:|err

 

[scott foxwell]

That 505 is a long way from a 454 in a car....

You're kinda mixing apples and oranges. You'll take whatever performance you'll get from that cam and snuff it out with a 4150.
Do you have flow numbers? What RPM do you want to run? Lot of cam for something not on the track.

 

[tunneljet]

I will probably throw a domi on it once I sell the heads and turbos I have for sale. Still got a lot of time as I am in Illinois. I don't have flow numbers but I was hoping to spin the motor less than 6500. I have an aggressor C impeller in it now. I don't mind changing the cam or the impeller but would like to avoid changing both if I could.

 

[Bruise Brothers Dad]

That 505 is a long way from a 454 in a car....

You're kinda mixing apples and oranges. You'll take whatever performance you'll get from that cam and snuff it out with a 4150.
Do you have flow numbers? What RPM do you want to run? Lot of cam for something not on the track.

Yea I know it's apples and oranges, but that cam will work with both. In the next note he says he only wants to run 6500. that cam is good to about 7400 + or - 200 rpm. I was using stock iron heads (LS6) no port work just massaged the bowls. I would run the 4500 carb with a single plain manifold. Back in the day Ross Wilder and Tom Papp explained to me that jet pumps work in the 7000 range ( top end). I'm not that knowledgeable about jets, but I have known people to run higher RPM's. He says he is only going to hodrod but we all know that it's racing when somebody next to you is doing the samething The motor that was in the Camaro also has been in a boat. Sometimes it's easier to just swap motors than to changes alot of thing when we are on a budget. I don't know it all, but have been doing it a long time but can alway learn something new. Got any secrets for me???

 

[Bruise Brothers Dad]

I will probably throw a domi on it once I sell the heads and turbos I have for sale. Still got a lot of time as I am in Illinois. I don't have flow numbers but I was hoping to spin the motor less than 6500. I have an aggressor C impeller in it now. I don't mind changing the cam or the impeller but would like to avoid changing both if I could.

Where is Shorewood. I have a half mile of river front property on the Kaskaskia river south of Vandalia

 

[scott foxwell]

I will probably throw a domi on it once I sell the heads and turbos I have for sale. Still got a lot of time as I am in Illinois. I don't have flow numbers but I was hoping to spin the motor less than 6500. I have an aggressor C impeller in it now. I don't mind changing the cam or the impeller but would like to avoid changing both if I could.

Without flow numbers you're throwing darts at a dart board blindfolded, especially if the heads were ported. A C impeller is very small for a lake/river hotrod. The C will work for where that cam is going to want to make power and my guess is you're going to be well into the high 6000rpm range. Again, you've got some mixed and matched parts there for what you say you want to do with the boat. Under 6500 would be more reasonable with a B impeller which is in the high 700hp range and probably going to put you over 100mph, depending on your setup. Personally, I'd get the flow numbers on your heads, cam the engine for no more than 6500, but also to make a very wide power band (which the cam you have now will not have), and run no smaller than a B impeller. With those heads and your engine displacement and compression, you should be able to make close to 800 with a single Dom. at that rpm with a much more reasonabel cam. It'll be easier on valve train, have more reliability and drivability and be more reliable. It'll also be plenty fast.

 

[tunneljet]

Thanks for the reply STEEL and Bruise. Shorewood is about 30mi southwest of Chicago. I have been down to Lake Shelbyville which is part of the Kaskaskia and I have inlaws in Fairfield and Edwardsville. I am on a limited budget, is there a cam that you have in mind that would work well for me. This setup was in a car but the engine builder ran jetboats at Blarney Island for about 20 years and felt that this cam would work pretty good in a Jetboat.

 

[scott foxwell]

Any cam will "work" in both applications, but there's no way one cam will work equally well. Jet boats do require a different approach to making power, and for most jets, 7000rpm is a MAX rpm, not a preferred or even desired RPM. That's pretty much hard core race territory. It's better to build more usable power at a lower rpm and keep things below 6500, or even down to 6000 for most applications. The more power you can make at a lower rpm, the better, but that's really true in all of racing. You don't have the luxury of gears or prop changes with a jet, so your rpm is basically dictated and you need to learn to build as much power in a limited rpm range as you can. Tis is why displacement usually wins over dynamic engine design issues that might otherwise dictate a particular engine configuration.
Now if I told you my secrets, they wouldn't be secrets, would they.hand

Yea I know it's apples and oranges, but that cam will work with both. In the next note he says he only wants to run 6500. that cam is good to about 7400 + or - 200 rpm. I was using stock iron heads (LS6) no port work just massaged the bowls. I would run the 4500 carb with a single plain manifold. Back in the day Ross Wilder and Tom Papp explained to me that jet pumps work in the 7000 range ( top end). I'm not that knowledgeable about jets, but I have known people to run higher RPM's. He says he is only going to hodrod but we all know that it's racing when somebody next to you is doing the samething The motor that was in the Camaro also has been in a boat. Sometimes it's easier to just swap motors than to changes alot of thing when we are on a budget. I don't know it all, but have been doing it a long time but can alway learn something new. Got any secrets for me???

 

[IMPATIENT 1]

That 505 is a long way from a 454 in a car....

You're kinda mixing apples and oranges. You'll take whatever performance you'll get from that cam and snuff it out with a 4150.
Do you have flow numbers? What RPM do you want to run? Lot of cam for something not on the track.

x2 on thatdevil why not just be patient wait it out bit longer and just buy a progressive linkage 1050? if you know anything about airbleeds, there's no reason you can't get the same mpg outta 1 of those compared to a 4150 stretched all out.

 

[scott foxwell]

Thanks for the reply STEEL and Bruise. Shorewood is about 30mi southwest of Chicago. I have been down to Lake Shelbyville which is part of the Kaskaskia and I have inlaws in Fairfield and Edwardsville. I am on a limited budget, is there a cam that you have in mind that would work well for me. This setup was in a car but the engine builder ran jetboats at Blarney Island for about 20 years and felt that this cam would work pretty good in a Jetboat.

Like I said, that cam (and I love this comment) "would work pretty good", if you want to turn 7000rpm with your C impeller and have a boat with a racing personality.
I can't begin to guess at a cam without flow numbers. Can't even use the factory advertized numbers since the heads were ported. For the rpm range you want to run in, something more in the 260-265 range, but lift will be directly related to flow. If they flow really good, could be below .700, but not going to guess.
Your desired rpm operating range will dictate your impeller choice. Your impeller choice will dictate your power requirements, and your power requirements will dictate your engine build/cam choice. It's that simple.
You have 500+ cubic inches...enough displacement to make good low rpm power. You shold take advantage of that especially in a jet.

 

[tunneljet]

I don't really want a racing personality in my engine. I figured I would probably end up changing cams, as I agree the slower I can spin the motor and make good power the better. I am lookin for something that will be more friendly than all out power. The heads were described to me to be fully worked. I can try the builder next week for some numbers if he has them.

 

[The Hat]

Sounds like a good place to Start, 110 lobe centers in a BBC is good, the lift and Duration is close, what Spring pressures at installed height? ...VERY important to keep GOOD springs and GOOD seat pressures, that same combo in a 3800lb Chevelle ran a 9.70 no Nitrous in a friends 502 with a 4:56 gear ......thats not going to be a low RPM cam, but that combo with C12 VP or C14 VP and a close pump will set you back in the seat pretty hard., most Jets need RPM. give it a try.

 

[scott foxwell]

Sounds like a good place to Start, 110 lobe centers in a BBC is good, the lift and Duration is close, what Spring pressures at installed height? ...VERY important to keep GOOD springs and GOOD seat pressures, that same combo in a 3800lb Chevelle ran a 9.70 no Nitrous in a friends 502 with a 4:56 gear ......thats not going to be a low RPM cam, but that combo with C12 VP or C14 VP and a close pump will set you back in the seat pretty hard., most Jets need RPM. give it a try.

Most jets need rpm? "It worked ion a Chevelle (or Camaro) so it'll work in a boat"...
Really?

 

[The Hat]

whats the fact it's in a boat have to do with it ?, think the engine knows what it's in?...LOL, all the Boat understands is power just like a car, they dont make cams for boats and cars, they build a profile for "RPM" ranges , and where you want the engine to work ....thats all...

 

[GT Jets]

whats the fact it's in a boat have to do with it ?, think the engine knows what it's in?...LOL, all the Boat understands is power just like a car, they dont make cams for boats and cars, they build a profile for "RPM" ranges , and where you want the engine to work ....thats all...

Well...

1. He didn't say "boat", he said "jetboat", while the engine won't know it's in a boat, the pump will be sure to whisper in its ear that it aint shit....A jet pump requires a balance of horsepower with sustained torque at the top end, most automotive engines can have torque fall off on the big end because the torque requirement falls off as RPM come in to play. A jetpump does the opposite.

2. The question was, will "this" cam work in "this" application...The correct answer is "maybe, what are the details of the build".

I will say it takes a lot of balls to jump in the middle of a debate of this nature though...devil

GT hand

 

[The Hat]

dont confuse low "speed" perfomance and quick acceleration off the line with "Low end" Horsepower, Low end horsepower is Low RPM power like a Diesel compared to a Gas engine, the Diesel makes LOTS of Torq, not a lot of HP, the Gas makes HP, but NOT a lot of Torque,

Generally speaking, low RPM power is just above idle to say 4000 rpm RV cam, Mid Range is from say 3500 to 6500 street strip,solid or hydraulic, or hydraulic roller, and Top end RPM is 5000 and UP "Roller" depending on many factors of course, but this is a sample of what I am saying, I used to spin a Blown Alcohol 557 cu in Chrysler to 8600, with a 4.5 in stroke, and a 1.51:1 Rod to stroke Ratio.....that worked for me, and the Cam was a simple 114 lobe center Crane R296 cams are MUCH bigger now and Valve springs have improved considerably. a lot also depends on the pump you are running, and that area isnt a specialty of mine....

 

[scott foxwell]

whats the fact it's in a boat have to do with it ?, think the engine knows what it's in?...LOL, all the Boat understands is power just like a car, they dont make cams for boats and cars, they build a profile for "RPM" ranges , and where you want the engine to work ....thats all...

How does the fact that it ran good in a Chevelle make it good for anything but the Chevelle it ran in? Maybe boats and cars have different power requirements? Maybe that engine worked great in the Chevelle but maybe it would fall flat on it's face in a jet boat? Buncha maybe's, eh?
I don't deal in maybes, and I don't give advice on maybes.
Did you read above where the OP doesn't want a "race boat" or "high rpm"?

I get this vision in my head:

"Hey Billybob...lets pull the moter outa the race car and throw it in yer boat. Man, that thing'z gunna haul ass! Hey, got any vice grips...this here moter mount is loose..."sphss

 

[scott foxwell]

dont confuse low "speed" perfomance and quick acceleration off the line with "Low end" Horsepower, Low end horsepower is Low RPM power like a Diesel compared to a Gas engine, the Diesel makes LOTS of Torq, not a lot of HP, the Gas makes HP, but NOT a lot of Torque,

Generally speaking, low RPM power is just above idle to say 4000 rpm RV cam, Mid Range is from say 3500 to 6500 street strip,solid or hydraulic, or hydraulic roller, and Top end RPM is 5000 and UP "Roller" depending on many factors of course, but this is a sample of what I am saying, I used to spin a Blown Alcohol 557 cu in Chrysler to 8600, with a 4.5 in stroke, and a 1.51:1 Rod to stroke Ratio.....that worked for me, and the Cam was a simple 114 lobe center Crane R296 cams are MUCH bigger now and Valve springs have improved considerably. a lot also depends on the pump you are running, and that area isnt a specialty of mine....

Um...aw, never mind. It's still the holiday....hand

 

[GT Jets]

dont confuse low "speed" perfomance and quick acceleration off the line with "Low end" Horsepower, Low end horsepower is Low RPM power like a Diesel compared to a Gas engine, the Diesel makes LOTS of Torq, not a lot of HP, the Gas makes HP, but NOT a lot of Torque,

Generally speaking, low RPM power is just above idle to say 4000 rpm RV cam, Mid Range is from say 3500 to 6500 street strip,solid or hydraulic, or hydraulic roller, and Top end RPM is 5000 and UP "Roller" depending on many factors of course, but this is a sample of what I am saying, I used to spin a Blown Alcohol 557 cu in Chrysler to 8600, with a 4.5 in stroke, and a 1.51:1 Rod to stroke Ratio.....that worked for me, and the Cam was a simple 114 lobe center Crane R296 cams are MUCH bigger now and Valve springs have improved considerably. a lot also depends on the pump you are running, and that area isnt a specialty of mine....

I think you are OK in the understanding of the low end vs. top end HP deal..

Here in lies the issue...Torque is a multiplier for HP, as is speed, so it would stand to reason (and correct me if I am wrong) that as the RPM gets higher, the torque subsequently falls off, in a pump type scenerio, the torque must be sustained at the higher RPM because the pump requires said torque to gain more RPM, the engine load (called brake horsepower) is linear and does not fall off.

IMHO to get the right combo, you first need to do all the math and figure out at what RPM your peak HP numbers meet up with the peak torque, then "adjust" the impeller cut and other periferals of the pump to use "this" info.

You could pull a motor out of a drag car or a really good running Vee drive and it wont work "out of the box" in a jet...It is a different animal all together.

Not to defend Steel (he never seems to need it hand ) but what he is saying is there is more to it than that......There is really no such thing as a majic camshaft grind that will work in everything...But that would be cool..devil

GT hand