400hp with a stock cam...believe it or not?

I wouldn't say "that claim is indisputable" and Dyno data does not suggest this either. If so you would see F1 and IRL running carbs on their cars - as for nascar they are limited by their rules to run carbs and Top Fuel does use Fuel Injection.
Walz
 
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400 flywheel HP sounds reasonable with no accessories.

Start bolting that engine up to a trans then put all the street car accessories on there and you will prolly be down to low 300s at the wheels.

I would bet much lower than that. If 300rwhp was as easy as bolting on a set of AFR's and doing a carb swap, everyone would have a 12-second Mustang right now.

I'd bet its closer to 250-265hp at the wheels at the very most.
 
I would bet much lower than that. If 300rwhp was as easy as bolting on a set of AFR's and doing a carb swap, everyone would have a 12-second Mustang right now.

I'd bet its closer to 250-265hp at the wheels at the very most.

You think so? An aggressive carb intake + AFR 165s should make high 200s id think. Especially with 1.7 Rockers. Dont GT40s Put out like 250-265 with a nicely matched intake?
 
Well...here's my take on this carb thing you guys are on.

My buddy's 347 has Victor Jr heads and a Systemax intake, plus a custom cam to match. It's EFI. Here's his dyno compared to mine:

View attachment 265070


Both are dyno tuned. Now, is someone going to tell me that if i step up to some AFR 185s, a Victor Jr carbed intake, and a 750dp, that i'm not going to make 400-420 at the wheels? I won't pick up 50hp with better heads, better intake and more carb? Why is it that my fuel curve is almost dead nuts perfect, yet carbs do such an inferior job at metering air and fuel? I've seen a lot of EFI ratios on dyno charts and they don't ever look any more flat than mine does. His hp and tq curve isn't any more broad than mine either.

I dunno...i think some of you guys are a little hard on carb setups. Yes, EFI is superior, but not so much that it will always hands down be better than a carb setup...IT'S ALL IN THE TUNING. I'm looking at an EFI setup with better heads, a better intake, and a more radical custom cam and it's only making 20hp and 35ft/lb more than my old school iron headed carb setup. My fuel curve looks excellent, my drivability is great. What more can you ask for? Can i drive into the mountains and get the same performance? No, but who the hell really drives their car from below sea level to 3k above anyways? I don't drive it in the winter so who cares about that?
 
I wouldn't say "that claim is indisputable" and Dyno data does not suggest this either. If so you would see F1 and IRL running carbs on their cars - as for nascar they are limited by their rules to run carbs and Top Fuel does use Fuel Injection.
Walz

F1? What did I say about forced induction and cherry picking examples?
 
I do not agree with your statement, carbs work on vacuum to meter their fuel, they intentionally design restriction into them in order to do their best at metering fuel. An EFI is a lot less restricted than a carb setup for this reason - on top of that metering/controlling the AF and timing can be a lot more precise/optimal which will produce more HP.

I will agree that it is a lot less expensive to produce more HP with a carb than an EFI setup because of limitations of the factory equipment and costs of equipment/components to upgrade.

Walz


I think your logic of how a carb works is on track but maybe a little off. They don't technically work on "vacuum", they work on atmospheric pressure (which of course, creates vacuum). I'm not picking a fight but what exactly do you think is a restriction in a carb? Also remember that carb sizing is key in making the best performance. Yeah, a 500cfm carb on an 8k race engine would be a restriction...but an 850 wouldn't necessarily be.

Typically, EFI makes more torque and has a broader torque curve...or in other words makes more torque at lower RPM and carries it longer than a carb setup...this is mostly due to the longer runners in your typical EFI intake. Build an EFI setup with a carbed intake that's drilled and tapped for injectors and run a throttle body on top of it, and there wouldn't be ANY difference here depending on the combo. Of course, the more radical you get with cams and air flow and RPM, the harder it gets to make a carbed setup streetable....again, i'm not saying carbs are better, just not as inferior as some people make them out to be. You surely could build 1000hp EFI engine and tune it to purr like a kitten, whereas you're not likely to build that kind of power with a carb and have it very streetable.

There's a line somewhere, where the performance gets to a level where no amount of tuning can make a carb run as well as EFI for all around driving. For max power and racing, there's not so much of a line. For your typical enthusiast, building a typical 300-400hp engine, it's down right silly to say you can't build a carbed setup to run as well and be as drivable as an EFI setup. You WILL get better mileage with the EFI setup...i'll give you that, but again a LOT of that is in the tune and making sure the a/f ratio is spot on. If it is then the carb is doing the same thing EFI is doing, except mechanically instead of with an ECU.


I really wish i could afford a Webber setup so i could really stir the pot :rlaugh:
 
its a general rule of thumb that EFI cars make more torque, and carbed cars make more peak power, you can bench race till your blur in the face, but at the end of the day, go to the drag strip and tell the guy with the single plain/Dominator setup that he is doing it all wrong.

Look at a Victor race single plain manifold, then look at say a Victor 5.0, tell me which one you think will make more power?
 
I promise you that once the big dogs in the NHRA and NASCAR can afford the extremely extensive R&D cost, they will go EFI. Just watch over the next 5-10 years.

They have the bucks to do it now and would like to. NASCAR prohibits any electronic controls on the cars because it is too easy to cheat. NASCAR would have to provide at least 100 computers and control systems, sensors and wiring harnesses to the teams on any given weekend and they would all have to be identical. It's too big a job to do week after week.

Short tracks, intermediate and super speedways would all require completely different computer trims too. It would be a huge job to use them.
 
I do not agree with your statement, carbs work on vacuum to meter their fuel, they intentionally design restriction into them in order to do their best at metering fuel. An EFI is a lot less restricted than a carb setup for this reason - on top of that metering/controlling the AF and timing can be a lot more precise/optimal which will produce more HP.

I will agree that it is a lot less expensive to produce more HP with a carb than an EFI setup because of limitations of the factory equipment and costs of equipment/components to upgrade.

Walz

The advantage to the carbs in peak is nothing more than atomization. EFI cannot atomize fuel like a carb...period. EFI does have many other advantages over a carb which give you more hp at different rpm ranges but until there is an advance in the actual injector..carbs will alway have the peak hp advantage just because of atomization. Check out the article below, there are alot of facts presented.

http://www.pro-system.com/scoop92102.html
 
A carb is the perfect meter to sit on the engine, a carb (well tuned for app) will give more peak hp. The carb responds very well to engine demands, fuel inj. is based after the fact, 02 sensor is after the combustion cycle.
That 405 hp is most likly 325-335 at the wheels, I would take a better matched small cam or ci engine over a bigger miss matched engine anytime.
Just as I would take a carb over a efi, I have done both and the carb car is cheaper to build and generally runs faster, not to mention all the clutter of electrical garbage to have to work around on the efi car.
 
I really wish i could afford a Webber setup so i could really stir the pot :rlaugh:[/QUOTE]

Speaking of webber, this guy uses webber power plates for holley type carbs with unbeatable results.
Troy Patterson TMPCarbs.net TMP Carbs
 
Barry Grant just came out with a carb that has removable venturie inserts just like a Webber, so you only ever have to buy one carb and you can tailor the cfm to meet your needs up until the point where you would need a Dominator style carb. Still though the magic behind Webbers is that they're basically like mechanical fuel injection...one carb for each cylinder, infinitely adjustible. Their only downfall is the lack of a decent long runner intake setup, but they make up for it in high RPM power. Roush even makes a Webber styled EFI setup that has 8 little throttle bodies and an injector for each one.
 
I honestly think 5.0 owners are too quick to pull the cam for more aggressive profiles before they have maxed out what the stock cam is capable of.

To me if you have a stock cam or one at idle that sounds stock and blow the doors off of some thumpity cammed rig its says you know something about building an engine.
And on the other hand if your the one with the big thumping cam and some stock sounding car kicks your a_ _, you will feel like sheet.
 
I honestly think 5.0 owners are too quick to pull the cam for more aggressive profiles before they have maxed out what the stock cam is capable of.

To me if you have a stock cam or one at idle that sounds stock and blow the doors off of some thumpity cammed rig its says you know something about building an engine.
And on the other hand if your the one with the big thumping cam and some stock sounding car kicks your a_ _, you will feel like sheet.


Well you don't necessarily have to have a lumpy idle to have a rowdy cam...it's all in the specs. Heck look at the B303 cam...that's pretty tame yet it lopes like a SOB. Check out this clip:

YouTube - 1990 Ford Mustang LX 5.0 with FRPP B303 cam

That's a measly .480 lift and 284 duration and 112 lobe separation, and it lopes a hell of a lot harder than my .576 lift and 307/315 duration and 110 lobe separation. Why i have no idea...