Thought I'd put this up for all y'all. This months Car Craft has some results from changing a 650 Holley to a 750, on a 6400rpm max 347ci ford. Baseline time was 12.40's at 109. Swapping to a 750 gained them .4 seconds and 2.54mph of trap speed.

Maybe that'll help some of you tryint to decide which to get

 

Yeah, but I wouldn't expect 4 tenths off a 13 second or slower small block chevy, especially the mild type most people on this board build, unless you are building somethign really serious, cuz that little 347 they had was quite the high rpm screamer......thus requiring quite a bit of air. and they also swapped an old 650 DP to a modern 750HP, hardly apples to apples. However all things being equal swapping from a 650 to a 750 on a motor that NEEDS it will give you something you can feel, no doubt.

I'd say swapping to a 750 from a 650 is only worth it if you can get one used and cheap, or better yet, free like I did. $600+ for the new HP??? YIKES! Find one used. The best cost effective mod I ever did was install a 1inch spacer in conjuction with a milled off choke tower and ported upper venturi bores. Was worth at least 20 HP on the *** dyno. I'm itching to try one of those proform main bodies but at the moment I just cant' justify it (for my girlfriends camaro that is)

 

One thing I always find interesting about the carb comparisons in the mainstream car mags, is that there is never a comparison of a Holley style carb versus an edelbrock/carter. I've seen Holley vs. Holley, Demon vs. Holley, Holley vs. Q-jet, and Edelbrock vs. Edelbrock, but never Holley/Demon vs. Edelbrock/Carter, hmmmm... I wonder why that is? I also notice a plethora of edelbrock ads in each issue... I wonder if there is some sort of connection . The editors are even careful NOT to make fair comparisons of Holley vs. Holley/Demon carbs (i.e., they will also change other parts of the engine when they change carbs so not all variables are isolated in the test). It ticks me off that publishers are that afraid of losing sponsors. (I also notice this in gun magazines). I know that this post isn't particularly germane, but I just had to vent!

 

Yeah, well, they don't want to offend any advertisers!

"Love over gold" ain't very common in our day and age it seems.

 

Well here's a comparision that I did with my much loved
long time faithful Holley 715 vacuum sec carb and a nice used Edelbrock 750 carb. The Edelbrock runs just as good as the old holley did. I even exceeded my best MPH at the track by a lil bit.
I got the best readings on my car, so far with my Vericom
(on the street) { better conditions than the track}
With the Edelbrock.
It is smoother. It is better on gas. I did not have to f***k
with it to make it work. I still like my Holley, the Edelbrock is a great carb too. The frick'en parts and accessories are expensive!I expect to exceed the performance of my Holley with the Edelbrock, when I get the new transmission and converter installed. they're both going to get a fair shot.
I don't get paid by or advertize in Hot Rod or Car Craft.

 

EEEeeekkk!!!

You are just asking for the wrath of Jester to fall upon you for praising Edelbrock

I gotta close my eyes

I can't bear to see what is gonna happen

 

Yeah thats about what it comes down to. Edelbrock is the biggest automotive sponser out there just about. No one wants to **** them off by showing how badly so many of thier products suck. I even see magazines still using the Edelcrock Triangle of Fiery Death air cleaner. I have seen comparisons...but not in a magazine. Edelbrock loses rather badly.

As far as Fbird, I can't argue with his experiences. Wasn't there. I do wanna know what Holley this was tho. 715? Wasn't that one of those old screwy 1pc Holleys with a top cover plate?

 

No, it's an old Ford Muscle car carb from the 60's
Originaly from a Fairlane with a 427. List#3255-1

Simular to a 3310 but a little nicer idle circuits. I've tweeked it a bit over the years (quick change kit , jet extentions etc). Just keep moving it from car to car.

Breezed right through a smog check with it on my Fbird recently. (1980 specs)

 

Dude thats a 40 yr old OEM carb. It's junk to anyone except a Ford restorer...even if it is a Holley. No wonder you found a nice improvment from an Edelbrock...and good for you that you did...but I think thats a looong way from a good basis to compare to another brand.

 

Junk eh.... heea Hee,, don't think so.....

I've compared it back to back to 750 dp carbs, even hp series and it runs the same as. or better.

Still running strong...... Thats Y I keep it. think I'm going to own this Edelbrock for a long time too.

Just had the turbo 350 from my old big block 68 chevelle, 68 chevelle 70 1/2 firebird freshened up to throw into the 88 bird after smoking the th700r4. I've had that trans just as long as the carb. Couple new clutches and seals and a new B&M converter and she's good for another 30 yrs. I'll send ya a pic of some day-light under the front tires.

Stuff that works, doesn't get old..... just like old AFB's
Like I said I just keep moving this stuff from car to car.

 

If that old carb runs as good a Holley DP it only means you don't have enough engine to use a DP. For street use give me a properly prep Q-jet !

 

Actually, on comparing Edelbrock to Holley... or, anything else.

If anyone was paying attention to the May / '01 issue of Car Craft, the bang for buck issue, you'll notice that at one point they test an Edelbrock Air Gap / Edelbrock 750 Performer carb on top of an 8.6:1, Aluminum headed, 210/228* flat-tappet cam, with headers and such that made 392hp @ 5,600rpm and 403 TQ @ 4,500RPM. The test was meant to weigh the benefits of an aftermarket induction system over the stock iron manifold/Qjet.


Now earlier in the issue, they're testing the addition of the camshaft. Same heads, exhaust, compression, even the same air gap manifold.

Except, there's a 750cfm speed demon carb. on top.

Guess what, 403 HP @ 5,600RPM and 418.7TQ @ 4,400RPM.

OOPS. Car Craft just made an indirect comparison.

Now correct me if I'm wrong, but every single variable was the same, except the carb. And the Edelbrock made 10-15 less TQ and HP.

Did anyone else notice this? I almost fell off the ****ter.

 

The thing I liked about my Edelbroke carb was it idle quality. Above that, it was all Holley for me. The only Holley that even let me down was the Avenger. What a POS that was. Its pretty bad when you pull a 670 Avenger off, put a 750 DP on and gain fuel MPG!

 

Hmmm, If the AFB had billet venturies and some other high tech(demon) mods - I wonder if that would make a difference.

For those keeping score the Edelbrock AFB design has gone virtualy unchange since it's introduction by Carter in 1957.
My little 750 works like a beeaatttch.

Ron

 

Sometimes bigger is better . I have seen engines that are making good power make even more by putting on a bigger carb. How in the world would I know it made more power? Time slips.

 

Alright guys.........want a comparison testing for REAL? I'm going to the track this Friday (2nd). I have a brand new 600 cfm holley 1850 and a brand new edlebrock 600, I will make runs with both carbs. As far as I can tell the car feels much stronger in the mid range with the edlebrock, but stronger up top with the holley. So we'll see real E.T. differences Assuming of course i don't get my usual 2.6 60fts.