I’ve heard that. Just didn’t know if porting it would make it flow more/smoother compared to maybe an rpm
A little more oomph
- Thread starter jrc4y4
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I’ve heard that. Just didn’t know if porting it would make it flow more/smoother compared to maybe an rpm
MOPAROFFICIAL
Oogliboogli
Light weight, dissipates heat faster.. might flow a hair better in design but still considered a stock replacement or RV type manifold.
[1] The Perf intake provides a slight improvement over stock when properly used.
Properly used means that the rest of the engine components combine to make peak HP at 5600 rpm [ in a 318 ] or less. Some idiot will try & use the Perf on a 6500 rpm engine, & then blame the Perf for lack of top end....
[2] Holleys. Sigh. If they are so good, why is every man & his dog making better ones....When Edel copied the Carter AFB, they changed NOTHING because the design was perfect from day one....
[3] Some little known facts. Edel used to sell Holley carbs before they started making the AFBs. Holleys then got dumped. At the time that Edel was selling Hs, they compared a 600 H vac sec to a 600 AFB on a 350 Chebby. AFB made 17 ft/lbs more tq, 17 hp more & used less fuel doing it. Nuff said...
Properly used means that the rest of the engine components combine to make peak HP at 5600 rpm [ in a 318 ] or less. Some idiot will try & use the Perf on a 6500 rpm engine, & then blame the Perf for lack of top end....
[2] Holleys. Sigh. If they are so good, why is every man & his dog making better ones....When Edel copied the Carter AFB, they changed NOTHING because the design was perfect from day one....
[3] Some little known facts. Edel used to sell Holley carbs before they started making the AFBs. Holleys then got dumped. At the time that Edel was selling Hs, they compared a 600 H vac sec to a 600 AFB on a 350 Chebby. AFB made 17 ft/lbs more tq, 17 hp more & used less fuel doing it. Nuff said...
yeah my set up is a 0-5500 rpm setup between the cam and intake at least. I start losing power around 5300 or so. At least when it was dynod 15 years ago lol. And as far as carbs, several people just say it’s a perfume sprayer, who cares as long as it sprays? Then others will say they pick up .2-.3 swapping from afb to Holley. I dunno lol. Half of people saying 302 heads will be killer on my car. Then half saying the opposite
This makes absolutely no sense....its not like their jets change size over time or something, lol. If you know how to tune a Holley, they work great. I have not touched my Holley based carb in years, and I race a LOT.
furrystump
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Yeah, the carb no matter which will flow the same unless a part fails. One carb may roll better with changing conditions, but it is the conditions changing not the tune.
Simple answer, you are getting reply's from 2 types of people...the mostly stock street car/car show folks, and the street/strip racing folks.
The street/strip racing folks will 99% of the time suggest a Holley carb because they make more power. The only time they won't is if it is for a specific race class restriction that won't let them run a Holley. They would also never recommend 302 heads on a performance build because they are not made for it, there are soooo many other heads that are better suited for more power.
The mostly stock street car/car show folks like the stuff that originally came on the car, and don't know how to setup/tune a Holley carb so they bad mouth them. In reality, both carbs work (Edelbrock type and Holley type carbs), but from a performance perspective the Holley will make more power.
For some reason (unknown to me) these same folks think 302 heads are a performance upgrade...they are not. The intake ports on 302's are super tiny, I literally can't fit my thumb in them. 302's just don't flow enough air to make decent power unless you put a TON of work into them...even after that, they still don't make good power compared to any aftermarket head, or ported 360 stock head.
I hope that helps.
Edit: Since your car is mostly street, pick whichever carb you are more comfortable with. It probably won't be a big difference for you. If you are thinking about racing more then go with a Holley.
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That makes sense. I am more the street car/car show crowd. I like reliability and having a clean stockish look. I'm not trying to make a 12 second Scamp. I wouldn't mind touching the 13s though lol. And from what I'm reading, some ported 302 heads with bigger valves could make that happen with some more intake and exhaust. I should have clarified the goals. I do want to go faster. Not looking at making a 450 HP engine. Just figured if I'm messing with it this winter, these seemed like better options than current setup. Not going the aluminum head route, I would consider a magnum head swap. I rarely hear good coming from a 360 head on a 318, but I do hear it from time to time. I'm not loyal to either carb personally, I can tune an AFB but can't imagine not being able to learn how to tune a Holley. Thanks for the feedback.
Rat Bastid
Dunamis Metron
If this is what you think, then you should tell everyone to run a Quadrajet. Because it is by far the most tunable carb out there. It’s not even close. You can buy something like 110 or more secondary metering rods just to dial in the tune up. The problem is, after all that they are overly complicated and they won’t make 1 hp more than a Holley that is correctly tuned. The QJ suffers from the same thing that every other non Holley carb does. It’s float bowls are too small. Ditto the needle and seats. You can’t pass enough fuel to make a lot of power with them, and on top of that the single inlet is a limit. The fuel bowls sit right over the hot intake manifold, heating the fuel which is a power loss. And the fuel bowl is way too small. The floats hang the wrong way and they shut off fuel with acceleration. Using a QJ on a single plane intake poses incredible distribution issues because as the secondaries open, no matter how smoothly you dump all that air and fuel into an already chaotic plenum. There are more issues but those alone are enough to rule it out as a performance carb. Can you make them make power? Certainly. But they won’t make more power than a Holley, and as the power level goes up, the QJ falls behind very quickly. The Carter/Brock suffers from many of the same issues. We at least need to be intellectually honest when comparing carbs. They all have their limits. The Holley is simple, easy to tune, has huge float bowls that have 360 degrees of air circulation around them. They have a needle and seat for the primary and secondary bowls, and the sizes of needle and seats is quite impressive. You can calibrate a Holley to run on E85 or methanol. Air flow capability is for the Holley is second to none. Of course, this isn’t a defense of the Holley carb, but rather a short run down of features of a couple of carbs as a comparison. When performance matters there is no comparable carb to the Holley although many have tried.
Rat Bastid
Dunamis Metron
Tuning the Holley is relatively simple. Go to the carb forum and search there for the posts that Mattax has made. Read those and read the links he posted and you’ll find out it’s pretty simple to get a Holley to do what you want.
Dartswinger70
Well-Known Member
OR you could watch an Uncle Tony video...
Thank you for the breakdown! I have had issues with fuel percolation. But have had less issue since running a small spacer and header wrap on my fuel line. Considering going electric fuel pump at some point.
Rat,
Talking nonsense as usual.
Who suggested using a QJ? Not me. But just for the record, there are QJ cars running 10s.
Look up Cliff Ruggles comparison runs with a Holley 850 & one of his QJs.
Then the nonsense about small fuel bowls. Have a look inside an AFB/AVS/TQ sometime.
You got one thing right...the fuel bowls sit right over the hot intake manifold. Yeah, Holley does that with a lot of DP intakes.
'...by far the most tuneable carb out there [ QJ]. It's not even close'. Huh?
See what the late, great Joe Sherman said about AFB carbs. I have given one example of an AFB making more power than a Holley.
Aaah yes, the great 4150 Holley. The one that had no protection for PV blowout; that leaked fuel from the acc pump transfer passage. The one where the cork gaskets dried out, blocked passages & caused all sort of strange happenings. PVs made of rubber that can change it's resilience as it ages & change the cut in point. Or just plain crack & leak. Yeah, great design. When Holley made the later 4360, they took a leaf out of Carter's book & used the simple & reliable spring loaded power piston arrangement. Hmm.
The float in the QJ hangs he wrong way & shuts off fuel with acceleration? You mean like the primary float on 4150 Holleys! Ya didn't mention that!
For a general performance carb, you cannot beat a AFB/AVS style carb. They are reliable & stable carbs. They, along with the TQ & QJ, have an advantage over a Holley 41X0 carb that uses a PV. The instant throttle response will always be better with metering rod carbs. More crisp. That is because of the torturous flow path the fuel has to flow via the PV in a Holley to get to the booster. It takes longer. Fuel has to negotiate a 90* turn into the PV, then a 90* turn out of the PV. It THEN has to fill up the PVCR cavity until the fuel is high enough to actual enter the PVCRs. Finally, the fuel makes another 90* turn into the main well, where it is finally on it's way to the booster. This all takes time. Compare this to a met rod carb. The fuel sits above the jet. When the rod lifts so that the thin power tip is now in the jet, extra fuel flows & is carried along with the already moving fuel, makes two 90* turns [ not three ] & is in the main well. That is not the only benefit...On Carter carbs & QJs, the distance the fuel has to travel for full power is shorter than on a 4150 carb. Quicker response. And not to mention the desirable graduated response from tapered met rods to save fuel & give accurate metering, compared to the on/off all/or nothing PV. Also, these carbs have at least two & often three MABs to better atomise the fuel for more power & economy. Holley has one MAB. These carbs have their idle mixture screws at the idle discharge point in the throttle bore for very accurate metering. 4150 mixture screws are in the met block, a long way from the discharge point..
Talking nonsense as usual.
Who suggested using a QJ? Not me. But just for the record, there are QJ cars running 10s.
Look up Cliff Ruggles comparison runs with a Holley 850 & one of his QJs.
Then the nonsense about small fuel bowls. Have a look inside an AFB/AVS/TQ sometime.
You got one thing right...the fuel bowls sit right over the hot intake manifold. Yeah, Holley does that with a lot of DP intakes.
'...by far the most tuneable carb out there [ QJ]. It's not even close'. Huh?
See what the late, great Joe Sherman said about AFB carbs. I have given one example of an AFB making more power than a Holley.
Aaah yes, the great 4150 Holley. The one that had no protection for PV blowout; that leaked fuel from the acc pump transfer passage. The one where the cork gaskets dried out, blocked passages & caused all sort of strange happenings. PVs made of rubber that can change it's resilience as it ages & change the cut in point. Or just plain crack & leak. Yeah, great design. When Holley made the later 4360, they took a leaf out of Carter's book & used the simple & reliable spring loaded power piston arrangement. Hmm.
The float in the QJ hangs he wrong way & shuts off fuel with acceleration? You mean like the primary float on 4150 Holleys! Ya didn't mention that!
For a general performance carb, you cannot beat a AFB/AVS style carb. They are reliable & stable carbs. They, along with the TQ & QJ, have an advantage over a Holley 41X0 carb that uses a PV. The instant throttle response will always be better with metering rod carbs. More crisp. That is because of the torturous flow path the fuel has to flow via the PV in a Holley to get to the booster. It takes longer. Fuel has to negotiate a 90* turn into the PV, then a 90* turn out of the PV. It THEN has to fill up the PVCR cavity until the fuel is high enough to actual enter the PVCRs. Finally, the fuel makes another 90* turn into the main well, where it is finally on it's way to the booster. This all takes time. Compare this to a met rod carb. The fuel sits above the jet. When the rod lifts so that the thin power tip is now in the jet, extra fuel flows & is carried along with the already moving fuel, makes two 90* turns [ not three ] & is in the main well. That is not the only benefit...On Carter carbs & QJs, the distance the fuel has to travel for full power is shorter than on a 4150 carb. Quicker response. And not to mention the desirable graduated response from tapered met rods to save fuel & give accurate metering, compared to the on/off all/or nothing PV. Also, these carbs have at least two & often three MABs to better atomise the fuel for more power & economy. Holley has one MAB. These carbs have their idle mixture screws at the idle discharge point in the throttle bore for very accurate metering. 4150 mixture screws are in the met block, a long way from the discharge point..
Rat Bastid
Dunamis Metron
So much sillyness I won’t touch it all. I brought up the QJ because of all you can do with it. That’s called an example. Let me hit a few other things. You can buy floats for the Holley to address fuel movement and float rise. How do you address that with your carb of choice? You don’t. How do you address the fuel heating issue? You don’t. You complain about the power valve, but with a metering rod you can’t separate the fuel enrichment system from the main jet like you can with a power valve. How do you address fuel flow through the needle and seat on the Carter/Brock, TQ or QJ? You don’t. How do you the limited float bowl volume on those carbs? You don’t. If you build and tune low output engines the carbs you worship are fine. If you want to make real power and tune for it, a Holley carb is the clear, simple choice. And I know of many cars running 9’s on QJ’s and TQ’s. So what?
Me: Man I'd like to run faster, maybe hit 13s with my 318. Can I do it with adding 302 heads, and is it worth swapping to a Holley?
Forum: Carb X is dumb.
LOL guys, I'm a simpleton trying to push my 318 a little more. But I do appreciate the extra info as far as the details on carbs. I really had no idea the ins and outs on what separated the carbs from each other.
Forum: Carb X is dumb.
LOL guys, I'm a simpleton trying to push my 318 a little more. But I do appreciate the extra info as far as the details on carbs. I really had no idea the ins and outs on what separated the carbs from each other.
Rat Bastid
Dunamis Metron
Don’t worry, neither does Bewy. The Holley is simple, easy to tune and addresses the issues the other carbs have. I can’t make it any more simple than that.
Dartswinger70
Well-Known Member
I ran an average run o the mill 600 vac sec Holley on my 318. Yes it ran good,it was easy to tune. I dont think it was the best as far as MPG matter of fact i recall it taking 50 bucks 20 years ago to drive it around from friday to monday LOL! i still have that carb I like em. Im running a 750 edelbrock on my 340 though...I would say if ya wanna try a Holley try a holley if ya wanna try something else swap em out. its good to have a few carbs on the parts shelf for different applications. i think the basic formula is take cu In and double it thats your CFM. 318 x 2 = 636 600-625 size will run on a 318.
Rat Bastid,
If you had bothered to read the OPs posts, it was pretty clear with the parts he already has & his budget, he just wants a mild performance increase & not a race engine.
Of course you are not going to address what I said because it is all true & you have no answers.....& no clues.
YOU introduced the QJ into this thread, not me. I would not recommend a QJ for the OP because I get from the OP he is working on the KISS principle for his upgrade. The best carb in that case would be a Carter/Edel AFB or AVS. Reliable, easy to tune, great power with good mileage, will run for years without problems.
Now to address some more of your BS:
- so you know of cars running 9 & 10s with QJs. Well why did you mention the single float bowl/single inlet needle as a 'problem'??? If they can run 9s, that takes a lot of fuel & obviously the fuel system is coping.
- the Holley doesn't address the issue that AFB/AVS carbs have....because they do not have any issues to address. Unlike blown PVs in Holleys or the high IFR position in newer Holleys that gives inconsistent idle response.
- how do you address fuel flow through the n/s on AFB?AVS/TQ/QJ. Your stupid answer: 'You don't'. Correct answer: you increase the n/s size, same as a Holley.
- apparently, you have never seen the inside of Carter 4 bbl. They have cavernous fuel bowl volume. The AFB/AVS/TQ comes with anti surge baffles. And they do NOT need jet extensions to keep the jets covered like some Holleys; or special vents to stop fuel spewing.
If you had bothered to read the OPs posts, it was pretty clear with the parts he already has & his budget, he just wants a mild performance increase & not a race engine.
Of course you are not going to address what I said because it is all true & you have no answers.....& no clues.
YOU introduced the QJ into this thread, not me. I would not recommend a QJ for the OP because I get from the OP he is working on the KISS principle for his upgrade. The best carb in that case would be a Carter/Edel AFB or AVS. Reliable, easy to tune, great power with good mileage, will run for years without problems.
Now to address some more of your BS:
- so you know of cars running 9 & 10s with QJs. Well why did you mention the single float bowl/single inlet needle as a 'problem'??? If they can run 9s, that takes a lot of fuel & obviously the fuel system is coping.
- the Holley doesn't address the issue that AFB/AVS carbs have....because they do not have any issues to address. Unlike blown PVs in Holleys or the high IFR position in newer Holleys that gives inconsistent idle response.
- how do you address fuel flow through the n/s on AFB?AVS/TQ/QJ. Your stupid answer: 'You don't'. Correct answer: you increase the n/s size, same as a Holley.
- apparently, you have never seen the inside of Carter 4 bbl. They have cavernous fuel bowl volume. The AFB/AVS/TQ comes with anti surge baffles. And they do NOT need jet extensions to keep the jets covered like some Holleys; or special vents to stop fuel spewing.
jrc,
Some other tidbits about carbs, Carter 4 bbl in particular.
Carter had a vac sec model AFB in 1957, the first year of the AFB. I have one, pretty rare. It was quickly consigned to the dustbin of history....
Presumably because it didn't work as well as expected.
Try & borrow an AFB so that you can strip it down. Unlike a Holley [ or clones ] you will not need a pile of gaskets if you are careful. You will be amazed at the clever construction, the sophisticated yet compact boosters, how close the primary jets are to the venturiis for quick fuel delivery/throttle response. How it is impossible to mix up the booster bodies.
The AFB has an ingenious 'starter cct' in the secondaries to help reduce bogging; the Holley does NOT.
Some other tidbits about carbs, Carter 4 bbl in particular.
Carter had a vac sec model AFB in 1957, the first year of the AFB. I have one, pretty rare. It was quickly consigned to the dustbin of history....
Presumably because it didn't work as well as expected.
Try & borrow an AFB so that you can strip it down. Unlike a Holley [ or clones ] you will not need a pile of gaskets if you are careful. You will be amazed at the clever construction, the sophisticated yet compact boosters, how close the primary jets are to the venturiis for quick fuel delivery/throttle response. How it is impossible to mix up the booster bodies.
The AFB has an ingenious 'starter cct' in the secondaries to help reduce bogging; the Holley does NOT.
furrystump
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Carbs! You never hear people arguing about injectors and I think the worlds worse off because of it. The easiest carb to tune is…………….AVS. All the benefits of the AFB, but no counterweights. All out performance? You can get ANY of them to whistle Dixie if you spend enough time and $ on them, but in the end is it really the same carb? You may think I’m biased because I run one. Not true. Given the choice I would run a Holley, because it is much easier to have the external appearance of a stock carb and and flow a crazy amount. Much more aftermarket support. Cold air is still the cheapest way for you to get a bit of improvement. It also transitions along with any other future changes.
oh, no secondary enrichment in the avs like in the afb! Can’t believe I forgot that! It is problematic for me!
oh, no secondary enrichment in the avs like in the afb! Can’t believe I forgot that! It is problematic for me!
Thanks guys for the input.
I notice you race FAST. I am intrigued by the racing, and one of the big guys lives nearby I think here in Columbia, MO. Forgot his name but he was wearing the shirt and I talked to him at Menards lol. Anyway. With what these FAST guys are running, that's why I'm asking why couldn't I port the Performer Intake, the 302 heads, and get significant gains? That was really my original intention. I may have found some headers, which goes from the stockish look but still my engine wouldn't look over the top. It's obviously not all factory as evidenced by my pic, but I do like the low key look of what I have going on. Wouldn't mind doing the cold air like you guys are saying.
Rat Bastid
Dunamis Metron
A quick glance at any Holley carb website will expose your lack of knowledge. I can buy 20 different styles and sizes of needle and seats for a Holley, for about any application you can think of. Including bottom feed needle and seats and ones for alcohol. Can’t do that with the carbs you worship. There are what, 3 sizes of needle and seats for the Carter stuff? You lose on that one as well. Seen plenty of float bowls on Carter/Brocks and such. They aren’t as big a the Holley, nor can you add a needle and seat or float bowl volume if you need it like you can with a Holley. One tiny inlet is all you get. Of course, for the OP some of this doesn’t matter. I only added this to expose the folly of your thinking. The OP would be far better off with a Holley or clone than what he has. That’s my opinion. You don’t have to like it, but I have laid out as clear as possible all the issues the carbs you love have. Some can be overcome, others not. Also noticed that you have made another error. Your assertion that the Carter/Brock carbs are vacuum secondary is not true. You can parse it any way you want, but the secondary throttle blades are opened mechanically. That makes them mechanical secondaries. They use an air valve to control air through the secondary side, but they still mechanically open. At least get something right. I’m done with this thread and your nonsense and foolishness.
Edit: to read all of my response you have to open the top part of the post. I don’t know why that happened.
512Stroker
We are all here because we are not all there.
You dont need to pull the heads off the engine to replace the valve stem seals.
You want HP on the $cheap, add a 150 HP NOX shot kit.
furrystump
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My guess on the 302 head would be it is closed chamber? Somewhat easier to get quench? I have no idea on the port flow in that head. Honestly there are much smarter people, getting a ton of power when it comes to 318’s. I have no real experience with them. The big pitfall in any motor is matching components. 318 will not be pulling a ton of air compared to say a 444 CI small block, unless you spin it to the moon and to do that with any motor is complicated. So you kinda work backward. How much depression/vacuum can 318 CI make? If the head efficiently transfers that depression to the intake you don’t need more head flow. If the intake can efficiently transfer the depression to the carb base, you don’t need more intake flow. You can make things too big with 318 CI’s, 444 CI small block? Not really, you need all the head flow you can get out of a stock casting. I believe people under rate stock intake castings. Not that the aftermarkets aren’t better, but more of what a stock casting will support. I think a stock 68-69 340 intake massaged a bit with some plenum work will support over 500 hp on a serious effort, not a street car, motor. For an example of bigger is not always better. I had too much time on my hands last winter and decided to go BIG on an intake and by big I really mean absurdly big, without changing the exterior of the stock 340 intake. Would my Frankenstein flow more air that any stock small block intake no matter what you did porting it? Yep. Can I create enough depression/vacuum with the max CI limits of an LA small block or possibly spin it fast enough to keep the velocity up? Probably not! I lost 2 tenth’s with it. I should of just drank beer and sat on the couch, but I have recently seen a very high dollar, manifold, modified by very well known brand name company, that shockingly, gives me reason for slight optimism!! So! No couch and not too much beer for me this winter!! Here’s my Frankenstein intake post.
Intake design for stock appearing class and needed a winter project
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