Dual quads

[ouh506]

I love the looks of dual quads.
Right now I have 2- 450 cfm Holley's on a 350 chevy with a rv cam seating on Offenhauser
Ram Induction Adapters.
Big bog right off idle or when trying to pass a car. And I am getting 10 mpg.
So I am thinking about using 2- 350 cfm two barrels.
Will the 2 barrel carbs bolt "in line" to my dual quad manifold ?
Will I get better mileage ?
How about a single 4 barrel 750 cfm ?

 

[choppedtop]

I am running a stock 350 with rv cam with a 600 cfm Edelbrock. Plenty of carb. Mileage runs 16 to 21 mpg, depending on road speeds. 55 to 60 mph, 31 mpg..70 to80 mph, 16 mpg.
Lee

 

[one finger john]

???????????????? Deja Vu ? I think not.

John

 

[ouh506]

Deja Vu
Am I missing something ?

 

[2old2fast]

You might want to look through some of the threads already up on this subject ...
dave

 

[Mike]

Somebody is walkin' out of this one with a boo-boo lip, that much is certain.

I love the looks of dual quads.

Only it sounds as if there is a 'but' in there. As in, "I love the looks of dual quads, but this flippin' pig doesn't make enough torque to pull a sick prostitute off a toilet seat." Somethin' like that?

Right now I have 2- 450 cfm Holley's on a 350 chevy with a rv cam seating on Offenhauser
Ram Induction Adapters.

So, in other words, you have some unknown camshaft, which was likely designed to be used in a truck pulling a large trailer, in a 350 CID engine, that would be over-carb'ed with a single 650 CFM carburetor, only you are using 900 CFM of carburetor, on 13.500" long ram induction adapters, which were designed for use in road race applications, which means they will absolutely kill any low-end power your camshaft is designed to build.

Yeah, that combination makes loads of sense.

Big bog right off idle or when trying to pass a car.

No! What with the way all of those parts were matched together? You're pulling our legs' right?

Watch this video, it's really short.

See those numbers, shown after the pull? That motor made peak torque at 4,700 RPM, and peak power at 6,500 RPM. Being honest with yourself, ask yourself the last time your motor saw either of those RPM levels.

Now, put that knowledge together with the simple fact that nearly every cam manufacturer that still offers something similar to an 'rv' cam has designed those profiles to work off-idle, up through about 4,500 RPM.

Will somebody, anybody, tell me how identifying a cam as an 'rv' grind is providing any kind of details, at all?!? @ouh506 , did you bother to read this post? Either you didn't feel it was necessary, or you are thumbing your nose at all of us, but in either instance, telling us you have an 'rv' cam is every bit as good as telling us nothing at all.

WTF does it take to make people understand? If you cannot provide us with complete details, we cannot provide you with advice to help you with your problem/s. Is it safe to assume before you came here to ask advice about this combination you refuse to tell us anything about, that maybe, just maybe, you tried to tune out your problem? If so, why can you not take the time to tell us what you have already tried? What, is this combination some kind of black ops deal, or are you just expecting us to have our crystal balls all polished up, and ready to go?

Hmmmm, now I am no rocket scientist, but if you have a cam that runs out of steam at 4,500 RPM, and an intake that wants to work really well at another 200 RPM above that, plus enough carburetor to feed air to your engine at 11,000 RPM, I am really wondering why anyone would waste time trying to make all those mis-matched parts work well together. Is coming to this conclusion really all that difficult?

Are you still wondering about the hole the motor falls into, when you open the throttle blades? Really?

And I am getting 10 mpg.

Well, that certainly sucks, doesn't it?

So I am thinking about using 2- 350 cfm two barrels.

I would think your thinking is, at the very least, a step in the right direction.

Will the 2 barrel carbs bolt "in line" to my dual quad manifold ?

Not knowing what intake manifold you have, and not knowing center-to-center on the pads, how can you reasonably expect any of us to answer that question? Yes, those carbs will fit, unless, of course they will not fit. In that case, then no, they will not fit.

Will I get better mileage ?

Not if you cannot tune the 2 bbl. carbs any better than you've tuned the 4 bbl. carbs.

How about a single 4 barrel 750 cfm ?

Other than obviously being too much carb for your application, I do not understand your question. How about what to do with a 750 CFM carb?

Determining carburetor requirements

Carb Advice

Another tunnel ram thread

Here, to save time, let me Google that for you.

And before you waste another moment of anyone's time, go read this post, paying careful attention to all four of those rules. And before you start whining about how poorly you've been treated, read this post.

 

[one finger john]

Sounds like this should be major sticky to be read before anything else.

You know who.

 

[fluidfloyd]

I've got a headache!

 

[Mike]

I've got a headache!

Welcome to my world.

 

[Bubblehead]

Ouh506- yep...I learned my lesson the hard way too by asking a question similar to yours. I had read all of the post here and other places about carb requirements and I too did not know what exact cam shaft I had because I had purchased the car and the "builder" is no longer available. Like you I was posting here in an attempt to get some additional opinions and options for my particular issue and learned that without a build sheet it was somewhat fruitless. Some offered some advice, but others chose to use me as a cat scratching post. Not a big deal, I'm a big boy. I wish you luck with your issue. -Glenn

 

[Mike]

Bottom line - no one is using anyone like a scratching post. But when people walk in the door, expecting realistic tuning advice without knowing anything about what they are trying to tune, then yes, someone is certainly using someone else.

We're not here to play guessing games, either on what combination of parts someone's unknown engine combo might be using, or on how it should be tuned. It is not going to happen. Period. Full stop. Fini.

Now maybe that is going to get someone's panties in a tuck. ouh506? You? I don't know. But, you see, it does not end there. Because, neither do I care. If you know exactly Jack Squat about what you have sitting right in front of you, then do not waste anyone's time, by expecting them to have a crystal ball, telling them what you do not know. I have no problem with you wanting to continue picking at this scab, if that is really what you want to do. We can dance the dance, for as long as you like. But if that is your decision, go into it with the full and complete knowledge that it is an argument you have already lost. Fair enough?

This isn't my first day on the beach with vague questions like these, Bubblehead. This kind of nonsense was my 8:00 - 5:00, for 37-plus years. Nine times out of ten, the guy who walked in the door to tell me about his 'RV camshaft' was actually running a stock cam, but was too embarrassed or ashamed to admit it. But he had to have an excuse why his alleged cam swap had such a buttery-smooth idle. So, to this very day, when these ears hear, or these eyes see someone talking about an 'RV camshaft', my first thought is that the individual is likely blowing smoke up someone's bum.

Everyone who ever sold a car to a Johnny-Racer, made sure that if the motor had a smooth idle, that was because they built the engine, late one Saturday night, and all they had was an 'RV cam' on hand. If the motor had a vacuum leak, causing a rough idle, then that was a motor with a '3/4 race cam'. And, naturally, that would also be the motor that had the 12.5:1 pistons in it. Of course, these were the motors we would pull down, only to find stock camshafts, and stock, cast pistons, inside.

Want to understand how all of this can be? Because in those 37-plus years, I learned a lot about car people. Real car people. The real, genuine, gear-heads. Those are the guys who have to know everything. They have to know how much compression their combination has. If that means jerking off a cylinder head to CC chambers and cylinders, then that is what they do. They have to know everything about their camshaft combinations. Not just lift and duration numbers, but where the cam is installed. They are checking rocker ratios, not just on one rocker, but on all of them. They are checking pushrod lengths, not on just one, but on all of them. They are checking valve spring pressures, not just on one, but on all of them. Just imagining they have enough bearing clearance is not good enough for them, they pull oil pans and caps to measure things. Whilst Mickey Mouthpiece is hanging out at the drive-in, or the car show, telling anyone hollow-headed enough to not care (understand???), about their 'RV cams', the gear-head is in his shop, working on his stuff, trying to make it better. It is real easy to spot the difference between the two, trust me. The gear-head is always going to be walking the walk, whereas the know-nothing is always going to be talking.

When a supposed car person cannot tell me explicit details about the heartbeat of their ride, I start wondering. Is this guy the kind of guy who cannot get a set of valve cover gaskets to seal, or is this just a guy who had a big enough wallet so he could afford to buy a car to tell lies about? The guy who doesn't know details, well, he is the guy who really doesn't care about the details. Likely because he cannot understand those details.

When someone tells me they have an 'RV cam', I figure they must have pulled the cam out of one of these -



I reckon the camshaft out of this RV would make a real rocket ship out of a stock motor, wouldn't it? Take that cam, a set of ported aluminum heads (oh, yeah, don't forget polished, ported heads always have to be polished), a tunnel ram with a pair of Dominators, bolt that into a T-Bucket, and it should be fast enough to travel through time. But, remember to leave the stock pistons in it, so we can run pump gas.

You let me know when you're ready to leave the sleeping dog be.

 

[one finger john]

Glenn, welcome to the real world. Here, in the real world, competent shops will charge you real money for an honest estimate of the repairs needed, even before the repairs are performed, because they know what they are doing. Here in the cyber world, lots of hot rod owners, who think there is a simple answer to everything, will pose the same questions as ouh506 has posted and expect a simple, exact answer to repair their problem. For little to no expense.

That is what it comes down to. You want to repair a problem on your car that you are not capable of performing. You go on line and ask someone who has more experience than you do to answer this question with you posting the bare minimum of info concerning the car. The more experienced person either says "come back with more information pertinent to the problem" or they will become tangled in a two page guessing game try to cypher what the original poster really wants.

So I think in the first line of everyone of these pleas I answer I will ask for a $100.00 just to get the estimate rolling and then an honest estimate of how much the owner has budgeted for these repairs. $200.00, $500.00, $2000.00, whatever. If they say they don't want spend any money on the repairs, o.k., no help for you.

If they don't have the necessary funds to complete the repairs then too bad, no advise for you.

I would still have my hunsky for my time.

Even Smoky Yunick, who used to be tech editor for Circle Magazine, eventually quit because he could not stomach answering another "my car won't turn left very well. why?"

And let's not even get into the apparent level of education some of these clowns are showing. One wonders how they got out of grade school. And now they are struggling to describe how to repair a vehicle that will be on a public highway, possibly endangering the general public itself.

This is a public forum on the internet. If some wants to ask how to do something they are certainly welcome to ask. If someone wants to answer this request with an appropriate answer then even better.

Be careful what you ask for.

John

 

[ellis8500]

When I started my project; thinking about an engine, I did a lot of research. First thought was get a high performance cam to replace the one in the stock Ford 302 from an F150 truck. As I soon found out there would be a whole lot more involved and many more $$$$$. I'd need new pistons and valve springs to accommodate the valve lift. Also might need new rods too. Maybe a stronger crank. One new thing after another and $$$$$. Also learned that carb cams are different from EFI cams. Found out that stock engine power is plenty for these light weight cars. I was not willing to pay a lot to tell people what was inside the engine. I was building a driver, not a show car. Ended up with a 1,200-4,500 RPM range cam, a 1,500-6,500 intake [almost new and cheap] and stock Ford E7TE heads. Put on a 600 CFM carb, which was too much for the engine. Never could get it to idle right [RPM too high] even with plates closed. Put on a 500 CFM carb and it works great.

If your going to do engine work on these cars as a hobby you have to do a lot of research and learn a great deal about how engines work and how everything has to match as a system. Buy and read some books. Nobody here can do that for you.

 

[Mike]

As tantalizing as the hundred dollar deposit sounds, we're not going to go that far. But, if someone comes along asking silly questions, offering silly details that are really not details at all, then that someone had better have his big girl panties on, because they are going to be treated in kind.

When I see some of the sillier questions asked on this forum, I am always wanting to lay odds on one of two things to happen. Either the person posing the question already has, or is about to have his wife/girlfriend/house mouse call the local parts store, to ask the same questions. I used to love those phone calls, because they always came when you were in the middle of doing something important.

Phone rings, and I answer.

Woman's voice - "Yes, my husband wanted me to call, because his car won't start. Can you help?"

Me - "What do you mean by saying the car won't start? Does the car turn over? Does it not turn over?"

Woman's voice, talking to husband - "Honey, the guy wants to know if the car turns over or not."

Me - "Ma'am, just put him on the phone, so we can stop playing telegraph, here."

If people want genuine advice, then they can learn to pose genuine questions, with genuine details about what they are working with. How the flyin' FLIP does someone who cannot fix the car sitting right in front of them expect someone in another state to be able to diagnose the problem? Answer me that one question.

Oh, so your car backfires through the carb? Is the choke working, because a lean condition can cause that. Is ignition timing correct, because early timing can cause that. Is there a broken rocker arm, or bent pushrod, both of which can cause that.

But yet, without knowing a single one of those details, we're supposed to just know what is wrong, and tell you how to fix it.

I am going to be totally honest, here. I know Jack about neurosurgery. Not a damn thing. Now, maybe you think less of me, but it is the truth. And guess what? When the doc told me there might be something wrong inside my head, I didn't run off to some medical forum, to post that I have screaming, painful headaches, and I need to know what's wrong. Nor am I trying to fix this stuff on my own. Because I do not know a bloody thing about any of it. I suppose I could blow smoke up everyone's backside and pretend I know something about it, but I don't do that. The reason I don't do that is because anyone with even a shred more knowledge that I have would be able to see right through my lame-ass B.S.

As ellis8500 just pointed out, none of us were born knowing everything. We just found the subjects we are passionate about, and we set about learning everything we could learn about them. If you really don't care, I'm good with that. Stop being a wedge-assed wooden-shoe, and go pay a local mechanic to work on your car. We do not exist to fix your car. Show some true interest, and we will try to help you, but stop looking for the free ride, when you cannot even tell us what you're working on. Do not waste our time by trying to pretend you can tell the difference between a brake rotor and a screwdriver. Whine all you want about being mistreated, but do not expect any sympathy, just because you are too stinkin' lazy to do some research of your own. And if that comment upsets you, go look in a mirror and ask yourself why.

Do your own research. Learn what you have. Learn exactly what is, or is not, happening. Then, and only then, will you be able to ask intelligent questions.

If people cannot ask intelligent questions, but then get wound up when they don't get intelligent responses, my only advice to them is to pound sand.

Know-nothings want to say this is being elitist, but they do that for a reason. They have to blame someone else for their problems, because they are not going to blame themselves for not taking some time to learn. And what all of this renders down to is this - if someone cannot be bothered to take the time to learn a little bit on their own, how does that make anyone else responsible for fixing the problems for them?

We are not going to have the life of this community sucked out by help vampires. It is not going to happen. And I think it is safe for everyone to assume that bikeshed questions are going to get called out, pretty quickly. Trivial nonsense will be answered, in kind.

 

[Bubblehead]

Got it Mike and thanks again for the lessons. I will no longer bother you or others with any questions and/or comments on this site. I wish you all the best. -Glenn

 

[Screaming Metal]

-----DAMN-----

 

[railroad]

We could have gotten him rollin, couldn't we Screaming Metal!

 

[one finger john]

But is Screamin' Metal empathizing with the OP or with Mike?

BTW, good to have you back SC. Check out Mike's thread on changing (just a little) the frame work of the forum.

John

 

[Screaming Metal]

Yea, we could've had him chasing his tail for days on that one! I knew when Mike said -Booboo lip-, nothing good was gonna come of this. Been around long enough to know that when you get Mike pissed....hey, it takes a lot....
Seriously guys, before anyone should come here and start wading in our pool, they need to know some basics. One of the reasons why I had to go take a vacation....is to decompress. I hate stupidity. But Stupidity is a temporary thing. Ignorance is permanent.

I don't build rocket ships, I don't do brain surgery, I don't shoot the center out of a quarter at 2 1/2 miles, I don't fly helicopters, I make things go fast. Done it alot of years. Was there when we cracked the 7 second mark in the 1/4, was there when we did 5...
We're even alot faster now.

dual quads this, dual quads that....knowledge is power. These folks oughta be armed with enough knowledge to keep from looking like fools. Theres no reason why someone should not look up how to run a TR if thats what they want or the old low rise 4X2 setups....
We have a damn good spiffy search button, the new folks need to use it before painting a big ole nice target on their forehead and their chest and back. All it takes is a little search time and a little reading to avoid this.
BUT, it does weed out the assholes and troublemakers, and Mike is way more nice than I'd be doing all this.
Mike, you deserve an Award....