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cam question

30K views 467 replies 51 participants last post by  Rexone 
#1 ·
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.
 
#2 · (Edited)
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
 

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#3 ·
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.
 
#5 ·
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???:(:(
 
#4 ·
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. :mad: 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.
 
#6 ·
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. :mad: 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
 
#8 ·
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.
 
#11 · (Edited)
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.
 
#12 ·
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.
 
G
#13 ·
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.
 
G
#15 ·
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...
 
#16 ·
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
 
G
#17 ·
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....
 
G
#22 ·
lets boil this down some, if the OP wants something, he needs to specify what it is he wants, define "High RPM"....we talking 6000 max?. 5500?....it all makes a BIG difference if he wants a Lake boat thats reliable and a daily driver, no that cams prolly NOT what he wants, but inorder to HELP the guy.,....he needs to give more info..
 
#23 ·
lets boil this down some, if the OP wants something, he needs to specify what it is he wants, define "High RPM"....we talking 6000 max?. 5500?....it all makes a BIG difference if he wants a Lake boat thats reliable and a daily driver, no that cams prolly NOT what he wants, but inorder to HELP the guy.,....he needs to give more info..

Ding Ding Ding, give the man a CIGAR........:|err

I am not really a dick in real life, I just play one on the forums.;)

GT:)hand
 
G
#25 ·
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.

the above question doesnt specify RPM and a 4150 Carb isnt something you want to run on a lower rpm engine, if you want this to run from say 2500-6500 RPM, then bench the 4150 and stay with an 850 double pumper, which would be much better suited, drop the cam down to something much more reasonable, but what kind of fuel you think this things going to run on and Not Murder it'self ?...it sure as HELL aint going to run on 93 octane pump gas, you have to make a complete combination in order for it to give decent results, the choice is yours
 
#33 ·
Steel makes very good points. Yes knowing the flow numbers of the head dictates what lift and duration will work with the head, Then you have to take into consideration what you want as far of power band, and what the boat or car is going to be used for. It boils down to combination. But I have taken old cams off my shelf and installed them with good results, not optimal but good. Do all your homework on what you are building, I always ask questions then make up my own mind. I have been lucky to be surrounded by alot of talented people most of my life and I have learned. Sure you won't cough up a secret or two Steel??? I may be old but I can alway learn something new.:(:(
 
G
#36 ·
It's clear you fellows arent interested in My input, and I am not nor do I have time to read every single post by an individual to determine what he wants,

I do have a few parting questions, if he doesnt want a Hot rod Boat and Motor combo, why in the Hell is he running 12:1 compression ?,

If he wants "lower Rpm" power, whats he doing with such Big heads on the engine ?

and WHY in GODS name would you run a Tunnel Ram on a lower RPM set up?.....

What I see here is someone who has been "tuned up" by so many others, he doesnt have anything resembling any logic involved in the end result that going to give him anything but headaches ,IMHO


Now I will just sit back and watch......
 
#37 · (Edited)
Why do you bother to (or how can you) offer advice if you're not going to read?

12:1 may be what it came with. Sometimes you work with what you have. Besides, 12:1 doesn't make it a hot rod.

310 cc heads are not big, especially on a 500" engine.

Where did you read anything about a tunnel ram? Even so, a properly tuned TR setup can be very drivable and provide very good usable power, given the right combination.

Actually what he has now would probably run pretty darn good...that cam, those heads and compression, and the impeller could be a pretty hard pulling hot rod if it's set up right (and if he leaves the dom. on it), but it won't be real "practical" or lake/river friendly for cruising and family use, and it doesn't sound like what he's asking for or interested in. The recommendations and advice have been offered in direct response to his questions.

Maybe you should just sit back for a while, and check out what goes on here. ;)
 
#45 ·
Since this is a lake/fun boat/hotboat
how about put the current setup in the boat and get a baseline, you can always re/cam the engine or carb setup after you get some numbers, every hull and impeller combo will want some tweaking, some want more or less cam and more or less carb, and there are a lot of things you can do with different impellers.

motor sounds like it will be healthy as is, race gas only deal, i would run it as is and get some seat time, it may be more of a ride than you think you have on paper.
Best of luck sounds like fun.
 
G
#39 ·
Steelcomp, here's a clue, 12:1 isnt a Pump gas combo, 310 heads arent a lake boat head, and YOU are no freaking Genius, then you go on to say the combo he has now would work.....isnt that what I said in my first reply? ...before you start kickin people in the shins Genius, make sure you know who it is you're talking to, and NONE of my posts till now have been Directed to you, but since you seem to have some Invisible Bone to pick with me, I've forgotten more shit than you know....Hotrod

I made it clear up front this is ALL about "Combinations", if you arent willing to knock the compression down and back the motor down everywhere then whats the point, ?, the ONLY unreliable issue he is facing in the Combo he states is keeping Good Springs on the Engine, the 70 Chevelle I used as an Example had a slightly bigger Cam and was a "DAILY" driver.......you need to Snap out of it Buckwheat and get over yourself.

enjoy life in my Iggy
 
#41 ·
LOL...wasn't it you that wanted to replace that 4150 with an 850dp?
You're kinda kickin yourself in the shins with your posts...and I agree...if you ever did know what you're talking about, you've certainly forgotten most if it mr. Crewchief...LOL...
No name calling on my part, and nothing was directed at you personally, but I'm very sorry you took it that way.

Buckwheat...LOL...good one.
 
#43 ·
Okay for basics 505cid turning 6500rpm will require 950cfm at 100%VE

505*6500/3456=949.7974...

So vs buying an adapter I'd probably by a progressive 1050.

Cam wise for a 505 at 6500rpm I don't think it's the best choice but as mentioned it will work (run).
 
G
#46 ·
Yo...Buckwheat...this is my FIRST post, wich YOU immediatly Challenged --->

"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."


you might wish to take your OWN advice, and Actually READ the post, and when you "QUOTE" someone, you are using their post as an example, either good or Bad, ......


heres another SIMPLE queston Buckwheat, when you Port a set of Heads, do you ask if they are going to be used on a Drag Car, Drag Boat or an Airplane, or is HP at given RPM the Barometer you use to Port Heads ?......

"your comment to me" -->(if you ever did know what you're talking about, you've certainly forgotten most if it mr. Crewchief...LOL...
No name calling on my part, and nothing was directed at you personally, but I'm very sorry you took it that way.)

I was giving advice to the guy who asked for it, it was YOU that chose to pick my advice apart rather than just give some of your Own.

and ANYTIME you want to compare Notes on who's done what and where...let me know.

Do You Bad mouth your Competion to get Business?, or do you Outrun them with Boats and Not your Mouth ?
 
#48 · (Edited)
OK...I'll be your Huckelberry.
Yes, I picked your advice apart, and here's why:

"Sounds like a good place to Start, 110 lobe centers in a BBC is good, the lift and Duration is close"
110 is good for what? and lift and duration...close to what, for what, in what?
Valve spring pressures are important...you're a wizard...

"that same combo in a 3800lb Chevelle ran a 9.70 no Nitrous in a friends 502 with a 4:56 gear"
...again, just because it works in a car has nothing to do with it working in a boat. Two different power requirements.

"thats not going to be a low RPM cam"...
well he already stated he wanted to lower the rpm range, so what's the point here?
...and what do you mean by "jet boats need rpm"?

Yes I challanged your first post...it was pointless.

Then:

"lets boil this down some, if the OP wants something, he needs to specify what it is he wants, define "High RPM"....we talking 6000 max?. 5500?....it all makes a BIG difference if he wants a Lake boat thats reliable and a daily driver, no that cams prolly NOT what he wants, but inorder to HELP the guy.,....he needs to give more info.."
So really, you don't even know what you're talking about. The OP gave plenty of useful info in his first two posts, which you clearly didn't read...yet you were giving advice, and now you're back pedaling...first the cam is "good place to start" then it's "prolly not what he wants..." so which is it?

Then this jewell:

"the above question doesnt specify RPM and a 4150 Carb isnt something you want to run on a lower rpm engine, if you want this to run from say 2500-6500 RPM, then bench the 4150 and stay with an 850 double pumper, which would be much better suited, drop the cam down to something much more reasonable, but what kind of fuel you think this things going to run on and Not Murder it'self ?...it sure as HELL aint going to run on 93 octane pump gas, you have to make a complete combination in order for it to give decent results, the choice is yours"
The rpm was clearly specified.
You still haven't answered the question about the 4150 vs. the 850 dp. and you're dropping that cam (again) that you said was a good place to start...
You're just all over the place.

Then, because you're all over the place and giving poor advice and getting called on it, you get all butt hurt and start pouting and get all arrogant:

"It's clear you fellows arent interested in My input, and I am not nor do I have time to read every single post by an individual to determine what he wants,
I do have a few parting questions, if he doesnt want a Hot rod Boat and Motor combo, why in the Hell is he running 12:1 compression ?,
If he wants "lower Rpm" power, whats he doing with such Big heads on the engine ?
and WHY in GODS name would you run a Tunnel Ram on a lower RPM set up?.....
What I see here is someone who has been "tuned up" by so many others, he doesnt have anything resembling any logic involved in the end result that going to give him anything but headaches ,IMHO

Now I will just sit back and watch...... "
As I said, if you're not going to take the time (and give the respect) to read the OP's info, then you have no business giving advice. This whole npost is just nonsense...especially the part about the tunnel ram, and where- in the beginning, he had a good place to start- now it has nothing resembling logic, and he's only looking at headaches. You've been so much help up till now, but suddenly, just s-hit can the whole thing 'cause it's nonsense...according to you.

And you sit back, looking down upon us all...

Then you get personal...

"Steelcomp, here's a clue, 12:1 isnt a Pump gas combo, 310 heads arent a lake boat head, and YOU are no freaking Genius,"
No one said anything about pump gas including the OP. Lots of guys mix pump and av gas or pump and race gas with their weekenders. Is it 100% practical? Not to me, but that wasn't part of the question, was it.
310 heads are considered relatively small on a 500" enigne, nd to say they're not proves you don't know what you're talking about. What makes a head a "lake boat" head, anyway? Care to elaborate on that one?
Thanks for pointing out I'm not a genius. Neither are you.

"then you go on to say the combo he has now would work.....isnt that what I said in my first reply?:
I went on to say it would probably work in a response to your stupid comment on having "nothing resembling logic", but also that it didn't sound like what he was lookiong for, and no, that's not what you said in your first reply.

"...before you start kickin people in the shins Genius, make sure you know who it is you're talking to, and NONE of my posts till now have been Directed to you, but since you seem to have some Invisible Bone to pick with me, I've forgotten more shit than you know....Hotrod"
All I can say to this is the same to you. You don't know me or who I am or where I've been and done. All of my comments in response to you were based on what you said, not at you personally. Don't blame me for your stupid answers or poor advice.

"I made it clear up front this is ALL about "Combinations", if you arent willing to knock the compression down and back the motor down everywhere then whats the point, ?, the ONLY unreliable issue he is facing in the Combo he states is keeping Good Springs on the Engine, the 70 Chevelle I used as an Example had a slightly bigger Cam and was a "DAILY" driver.......you need to Snap out of it Buckwheat and get over yourself.
enjoy life in my Iggy"
Again with the Chevelle...bragging about something that's completely irrelevant. Very impressive. I'm full of MY self???
What's your Iggy?

And finally I love this one:

"and ANYTIME you want to compare Notes on who's done what and where...let me know."
Just classic. Are you really all that, 'cause with what I've seen above, you sound like someone bringin a stick to a gunfight.

Nice way to introduce yourself to the group mr crewchief. There's a couple others here that you'll fit right in with.

:)hand
 
#47 ·
If I had to run that motor, as is, I would sell the jet and pick up a flatty with no engine..............:)bulb
 
#50 ·
Hey,

Its a party!!!!!!

Some things never change.............

Amazing part is you guys are pretty much saying the same thing.
 
G
#51 ·
steelcomp, it's clear you are in the wrong Line of work if you dont know Naturally Aspirated Big Block Cheverolets "LIKE" 110 degree lobe centers, and High Lift Cams, it's also Clear you are a self proclaimed Genius, but you avoided the real question , and that is, what have you actually DONE, besides attack others for their advice, How many Championships have you Won?, how many Races?, and in how many different categories ?, how many different Classes ? and how many Different Sanctioning Bodies, How many different Vehicles ?, all I see here coming from You is a bunch of Chin Music and Hot gases, someone who needs to degrade others to elevate themselves, and if you think Top Alcohol Engines in Boats and Cars are so different, you need to put down the Crack pipe, and GO to a few NHRA races to find out, expand the Little tiny little "Walnut" of yours, go outside your little Jet Boat realm you live in and find out, theres a BIG ole world out there and not everyone limits themselves like you do thinking inside the box.

"the BOTTOM line is, he has an Engine, he apparently Knows whats in it, he just doesnt know if his "Jet" boat is going to like it, all he needs to do is pour some GOOD VP C12 or equivilant (NOT Av Gas or Pump Gas) fuel in the Tank and and mount his carb and go RUN the dam thing, rather than Spending a few grand chasing something he finds he doesnt even LIKE, then if he wants to change it, He has a Baseline, not just Guessing from several people who are working out of a Box, thinking "this wont work and That wont Work".....I spent 45 Years proving Hot shots like you.......(WRONG) and been WAY more successful at it, than you have Dominating a Forum" .............Buckwheat
 
#52 · (Edited)
LOL...there ya go...attack the messenger, not the message.
Keep diggin, Hat. :)hand
Hey, you might be the greatest engine builder and tuner of all time, but the advice you gave above was all over the map, and in some cases just plain stupid. That's all I responded to, and you obviously have no explanation so instead, you attack me.
Pretty childish, don't you think?
 
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