I've been thru my 2nd Holley 750 Vac secondary square bore in less than 4000 miles. What's are my options for a mech secondary, 750 CFM square bore to go on my 454?

I'm leaning toward Edelbrock since I'm not partial to Rochester or Carter and not having any luck with my Holley.....

Holley 950HP(used). What was the problem with your 750 vac sec holleys?



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Chris Dagenais
Saskatchewan
'71 Malibu with a home built 454!
"Because of my velle, i'm broke, cut, bruised, tired, dirty, sweaty, and loving EVERY minute of it"
My Page (http://www.ycworld.net)

Not sure what the problem is, I got a freshly rebuilt one with the car when I bought it, the owner said he didn't like rebuilt carbs and put a new one in. The one in there now, I rebuilt friday and it didn't help, I still have way too much fuel loading up and fouling my plugs.. I'm tired of playing around with it, and also think I need mech secondaries anyway. This is as good a time as any for a change....

i'd have to agree, buy a used 950 if you can find 1, Grandalf has mine, and im missing it already (i swapped back to the 750vac. sec. for gas milage) but i lost a LOT of power, and it's pretty much a bolt on and go.

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1970 SS396 AKA 454/4spd
My Chev-Hell Page (http://hometown.aol.com/jnkb2cool/home.html)
Member #783
Ft.Worth, Tx
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Unless your strictly racing, and even then, you don't NEED mechanical secondaries. I would try and figure out what the problem is with your current carb. Have you done anything beyond putting a rebuild kit in it? Have you tried putting smaller primary jets in? Are you sure the float bowl level is not to high? There are basic things to check that are a lot easier than swapping carbs every time something is not 100% with the one you have.



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Chris Dagenais
Saskatchewan
'71 Malibu with a home built 454!
"Because of my velle, i'm broke, cut, bruised, tired, dirty, sweaty, and loving EVERY minute of it"
My Page (http://www.ycworld.net)

Check you float level. If it is too high adjust the needle and seat, if it won't adjust then take them out and look for dirt. If there is dirt on the needle and seat clean or replace and get a new fuel filter. Also try adjusting the idle mixture screws. If the float level is set then work on jetting and such. Don't forget to check your vacuume and get the appropriate power valve.

Steve R

[This message has been edited by Steve R (edited 06-10-2001).]

I suspected the floats, and set them as best I could "low" since I can't keep it running long enough to set them right. I have the floats set so no fuel comes out of the sight holes.....

Any other way of setting them? I'm going to replace my plugs tomorrow and try again...

One more thing, since I have less than 60 miles on my ENGINE rebuild, things that were changed were lowering the comp ratio from 11.25 to 10.5 and replacing the single plane intake with an Edelbrock Air Gap.

Maybe the jets are too big on the primaries and it just took this long to foul the plugs out....

Did you replace the floats? If they're the composite type, they may be sinking on you. What about the power valve? Are you running a big cam that's causing the power valve to open when it's not supposed to?

I may be wrong but I thought the jets only let fuel in when it is given throttle and not at idle.I always thought the idle circuit was different from the primary jets.I would look for a vacuum leak or make sure the throttle blade is not open too far at idle.Replace the floats and adjust the air mixture to get the highest vacumm reading.

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John 67SS
ACES #2887
Team Chevelle Gold #127

Just a FYI: an Edelbrock IS a Carter...

Big O Dave

I run 3310's on both my 70 SS's..they're great carbs IMO.Sounds like the one you have needs to be massaged a bit.Did you ever check that power valve?

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1970 Chevelle SS396/M21/4.10 My 70 SS396 (http://www.chevelles.com/showroom/mr4speed70SS1)
Engine pic (http://chevelles.com/showroom/mr4speed70SSengine2)
1970 Chevelle SS454My 70 SS454 (http://chevelles.com/showroom/mr4speed70ss454)
1968 Oldsmobile Cutlass convertible
1982 Oldsmobile Cutlass 350 Olds,TH350(daily driver)
Chris Corwel,TC Member 785

The more I think about this.. Now maybe I'm thinking power valve (the one in there is the stock 65 (I just replaced the 65 that was in there when I rebuilt the carb Friday), maybe there's not enough vac for it, I also have a .556 cam..

I'm also thinking maybe my elec choke may not be adjusted right..

Too many variables...

First thing, replace fouled plugs with some new autolites....

next????

Get the Edlebrock with vac secondaries. You will not have a problem with a carb again. They should make a label for Holley Carbs, that has that little boy pissing on a carb that has HOLLEY in bold letters on it. Don't know if I worded that properly but I think you will get the point. Good Luck Jon

What about the new Holley street avenger or the Edelbrock Performer carb????

I'd also investigate the power valve theory - you'll run very rich if it opens too early. You might also want to check your timing by ensuring that you're getting both vacuum and mechanical advance.

Jon you got that wrong it should be on Qjets. Lets see what that starts...FRED

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