Ok lets see just how far I can throw a 750 Holley.

[smoked68]

Alright I just remembered why I was running an Edlebrock carb now. For the last 2 weeks every time the weather has changed I'm messing with this carb to keep it idling. Its the humidity I guess and colder temps. It was set up in the summer and now its all outta whack. Any suggestions, its a 750 with vac secondaries. I'm thinking of going with the 850 Edlebrock. ??? I'm running a lopey cam and a Weiand 144 SC. Off idle its great, just won't idle, today! Tomorrow may be a different story. I actually set it 900 rpm a week ago, today it was hitting about 600 then wanting to die. Let me know how to fix this somebody soon, I'm loosing my ever lovin mind...

[1966gmc]

No suggestions here man sorry. I only run Edelbrock carbs

[71 super]

Hand held vacuum guage is your friend. Hook it to a vac. source and adjust mixture screws to highest vac. reading adjust idle screw and check vac. readings again setting to highest vac reading. Have you changed pwer valve out? Depending on vac. reading you may have to change to match the reading of your engine. Holleys can be work at times but they are the set up for a warmed over motor. You may also have to adjust the jetting and the rate at which the vac. springs come in for the secondaries. There are several good books on holleys and tuning them for max. performance. One last thing, is this a newer model 750 (3310-5/6) with power valve blowout protection? If not this is something you might want to invest in if you are driving the truck daily especially in cold weather, one pop back through the carb and power valve is gone and will cause the same symptoms you are having. Hope this helps, if more info let me know.

[lowriden58]

sounds like the air bleeds arent adjusted correctly. my truck would do something similar before it was tuned by a pro she would do fine when driving but idling she would want to die out, even with the idle bumped up.

[Gray Ghost]

Sounds like your Holley has a problem....that said, Edelbrocks are usually painless and don't have to be constantly adjusted. Bad news is they aren't as good when you stomp the floor with the pedal.

I didn't know Edelbrock made an 850 but I do know their 1407 [750] is a good one and it's jetted for performance like my 1405 [600] is.

[yotaforce]

Throw it up to Rutherford County NC, I'll catch it. I am a Holley guy. Ran "Brocks", but love the performance of Holley. I only had to adjust mine twice a year, hot to cold, cold to hot, day to day it was always a good carb. Haynes Holley manual is very useful to have around.

[smoked68]

I think its an older 3310, the guy who rebuilt it for me was supposed to use an updated kit that had the power valve protection you were talking about. I think? If not that could be, because it has popped a couple of times early in the crank up. I will also check the air bleeds. The floats have hung once a month or so ago so I ran some Sea Foam thru a tank. Much to think about, like that 850 Eddie is sounding better by the minute. I'm off next week, sounds like another project, rocker panels, mtr mounts now carb...Merry Christmas to all and thanks. Mike.

[smoked68]

Summit has the 850 Brocks, I have not priced but they show one on the Edlebrock SC crate engine they are selling... I likee the Holley I'm just relearning its little tantrums...

[Ryan Hubbard]

I used a modified 3310 on my blower motor and now I switched to a blower carb that has the power valve referenced to the manifold pressure. I found my 3310 would load up at certain times. I think you have a blown power valve, also you need to get a higher vacuum power valve also. Here is B&M supercharger manual on carb setup:

[70clone]

get a demon by barry grant

[DirtyLarry]

Yeah, I hate Holley's. I owned one once....once!

[dieselarmy13]

Holley shotput is one of my favorite sports.

[jsbgump]

Thats why I don't run holley's on mine. Too big a pain in the rear.

[caminokid]

easiest way to fix it is put a edelbrock back on. Cause of the same problem you are having right now...I almost lost my left hand. I was tuning a 650 and when i revved the 327 up...the fan broke and one of the blades went thru my wrist. Pretty f'd up. The Holley went bye bye after I got well.

here is the scar.


How far can I throw a Holley...all the way from my garage to the street.

[Gray Ghost]

Pretty good case for tossing that flex fan as well I'd say. We always hear about those blades coming off.

Sure am glad you still have your hand, that looks like it hurt quite a bit.

[caminokid]

Originally Posted by Gray Ghost

Pretty good case for tossing that flex fan as well I'd say. We always hear about those blades coming off.

Sure am glad you still have your hand, that looks like it hurt quite a bit.

That was in 91. Had a really bad year that year...long story and not enough bandwith on here to cover it! I stopped using original clutch fans after that too.

[Chevymann1968]

Originally Posted by caminokid

That was in 91. Had a really bad year that year...long story and not enough bandwith on here to cover it! I stopped using original clutch fans after that too.

I had a similar event happen to me butit wasnt a stock fan it was a flex a lite!!!! I was lucky though it hit the edge of the hood and was stuck in it!!! NEAR MY FACE!!!! GET AN EDELBROCK!!!

[68Stepbed]

What's the brand of carb got to do with fan blades coming off?

Anyway, I've run Edelburps and Holleys. Every Edelbrock carb I've had was nothing but trouble. I was told I could just setit and forget it. Well, for about 3 months(which is the warranty time) it was great, then they always tended to puke out on me, flood my engine alot, wouldn't idle right, ran rich and fouled plugs all the time. The final straw for me was when I was pulling into traffic and had to get on it to get up to speed when it choked the engine down and stalled on me in the middle of oncoming traffic. I bought a Holley that weekend. It's been a great carb with very little trouble. The carb I bought was a 570 Street Avenger. I'm still running the same carb on my engine now with a mild cam and it runs great.

I personally think your main problem is too much carb. 750cfm is way too much for any mild sb. 600cfm would be the max. The 850 Eddy you're looking at will cause you more problems later down the road. If your gonna get an Eddy carb, don't go any bigger than a 600

I'm not really gonna say that one brand is better than the other, but from my experiences, the Holley has worked better for me. The Holleys tend to get finicky while tuning, but once tuned right, their awsome carbs and you can get max. performance out of the Holley. The Eddys are good carbs for the guys who don't want to spend the time to tune a carb. That's why they seem to be more simple, but you will only be able to get decent performance compared to Holley.

IMO it's a trade-off. Either get decent perf. with little tinkering with the Eddys or tinker with a Holley some and get max. performance.

[QKENUF4U]

used to be a huge holley lover till i put a carter afb on my blazer. will never look back !!! its either carters or edel from now on.(when i have a carbed vehicle again)

[SactoJim]

Smoked69.....I have a similar setup (142 blower on a 383) and I'm running an Edelbrock 800 AVS that has worked perfect right out of the box. I've had Demon's and Holley's but decided to try something different this time cuz I've never had much patience to dick with carbs even though for the most part I've had good luck with the others. I've pulled plugs and they look just fine, but with the calibration kit you can get seperately and wideband O2 tuning equipment, you could really dial it in.

Most will say that you will get more HP out of a holley and I agree, but by the various tests I've seen over the years, you're not gonna give up a whole lot of ponies on a purpose built street motor when chosing an Edelbrock over the others.

I would think that a 750 vac secondary carb would work just fine for your application.

[leddzepp]

My dad threw a Holley about 50 yards when I was a kid. Then he walked over to his parts pile, and put a Carter back on.

[Wrenchbender Ret]

With a "lopey" cam you need a lot of spark advance. Get an adjustable vacuum advance or one for a performance Vette. Set it to come in at a low vacuum & hook it to full manifold vacuum.

[SactoJim]

Originally Posted by leddzepp

My dad threw a Holley about 50 yards when I was a kid. Then he walked over to his parts pile, and put a Carter back on.

Must of been pissed.....that's a long ways to throw a carb!...

Originally Posted by Wrenchbender Ret

With a "lopey" cam you need a lot of spark advance. Get an adjustable vacuum advance or one for a performance Vette. Set it to come in at a low vacuum & hook it to full manifold vacuum.

You guys forget he's got a little blower on it which will usually calm down a lopey cam and provide a better vacuum signal to the carb. You don't want to hook up your vac advance to the manifold either with a blower since it will usually see positive pressure created by the blower.....wanna hook it up at the base of the carb.

[Dice]

I have a speed shop and after 30 years of wrenching, I can't say that one brand of carbs is better than the other. They both have their quirks and can have problems if they aren't set up properly or get some debris in them. Here's the annoying problems I've experience with Edelbrocks: If the fuel pressure is slightly higher than stock, they flood over or run super-rich. Next, they're very sensitive to engine heat and if you don't have a good insulator between the intake and carb, they run erratic when hot. Finally, if you let your car sit for a few days, the gas magically disappears from the bowls and you have to crank them until the fuel bowls fill up again before they'll start. I prefer Holleys.

[AK72K10]

Had a 600CFM Brock on my K10, was averaging about 6MPG when I first bought it. The darn thing was pooling up, fouling plugs and causing run-on so I went on a rant and decided to research potential fixes. Luckily my father-in-law (Also a Mech-a-nic) lives with us, he recommended a Holley 600CFM, told me I could learn something about how to optimize my engine for performance and economy, so I picked up one on the way home from work on a Wed night. Thing is I never swapped out a Carb and when I walked in with the new one Pops just said "Looks like a weekend project" then he just shook his head when I told him I was going to do it right then and there. That was about 7PM, had to work the next day, was my only rig, and I live about 27 miles from work. Anyhow I jumped into it and after I had it installed, was able to get fuel & fire, the dern thing STILL had run-on! Dug up a manual on Holley carb adjustments (sure wasn't plug-n-play!), Pops had a cold one and gave me some more pointers, and at about 12 midnight I finally had it running like a top. Took it out for a test drive, my rear end nearly passed me when I pulled out onto the road in front of the house (And not just because of the ice on the road!), and it was then that I decided I would much rather work a little bit harder, adjust my Holley to it's "Sweet" spot, and get the performance I desired out my 350 then go back to my underperforming Edelbrock. Just like Ford Vs Chevy, Big Block Vs Small, Edelbrock Vs Holley, the list goes on, to each his own, as long as it eats up the pavement and you feel good about it, run with whatcha brung. Oh, one other thing, when the ole guy that has thousands of hours experience & and the been-there-done-that look on his face tells you "Looks like a weekend project" you might just want to slow your roll, take notes, and wait for Saturday.
AK

______________________________
1972 K10 Custom Deluxe 350/350
2008 Suburban LTZ White Diamond
1972 F100 302

"Why Build It If You Can't Drive It?"