73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: 82Shortbed on February 12, 2009, 11:42:00 pm
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I'm deciding against my quadrajet since it started ticking me off as of late. I am narrowed down to 2 carbs.
Here's the engine setup....
350 punched .030
Crane 100182 camshaft (.465/.465 286/286 230/230 @ 0.050 106LS)
Vortec heads with just a regular valve job, shaved .020, the valve guide bosses have been cut and Z28 springs are now on them.
Performer RPM intake for Vortec heads.
2200-2800 stall if that matters.
I'm down to either the 1406 Edelbrock (600cfm electric choke) or the 1411 (750cfm electric choke).
Had people tell me the 750 would be too much carburetor for the engine. I ran the 1407 (750cfm manual choke) on a '80 malibu with 882s and a 292 Magnum cam, ran pretty good with it, so that's what pushes me to the 750, this truck engine is gonna be way better than that malibu motor as well.
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maybe put an edelbrock
650 or a holley 670 and see what it does then goe to a 750 or just buy a 750 and put smaller jets in it
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I ran the 1407 (750cfm manual choke) on a '80 malibu with 882s and a 292 Magnum cam, ran pretty good with it, so that's what pushes me to the 750, this truck engine is gonna be way better than that malibu motor as well.
You answered your own question
Myself, I would rebuild the Qradra Junk
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looks like a 5800-6000 RPM combo . Am I close ? if so I think Id run either a Demon 625or a 650 Holley.
or a Q-jet if you have a spreadbore style RAPM intake.
If your dead set on an Edelbrock performer series carb, than Id run a 600 & try a 1'open spacer under it
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650 Holley with a spacer would be even better...
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The RPM intakes have a pretty large plenum, I think with 625 to 650 the plenum volume is more than enough on a 355, but a smaller cfm carb might like the extra volume
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You would want to keep conservative with the carb and keep it 650 or under on the CFM.
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I'm wanting to stay away from the Holleys, I know ALOT of people like them. I just like the simplicity of the edelbrock. I have had a few suggestions to the Holley 600 Electric Choke. Should I get a high volume fuel pump as well? Like the Holley 80gph set at 7.5 psi?
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stock pump will be fine for that application.
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A carb needs no more than 7lbs so anything over a stock pump is a waste of money.
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I have to agree with everyone else who says 650 or smaller. I have an edelbrock 1406 on my 383 and am happy with the carb. My engine runs out of cam around 5500 right now, but on a previous setup with more compression and a different cam that carb would make the motor pull until you took your foot off the throttle...took it up to 7000 one time...bottom end didn't like it. Anyway, the 1406 gets my vote. It will do what you want it to do.
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I'd go a little bigger on the cam and use the edelbrock. Stock healthy pump is fine.
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I did a little reading, edelbrock suggests no more than 6.5lbs of fuel psi so I will just new a brand new stock profile pump. I've had alot of people suggest the 600. I dunno whether to go manual or electric choke, I read the manual is a little more aggressive tuned.
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I say look at the Holley avenger series 650cfm or 670cfm
I have the 1405 holley which is 600 cfm I had to put a bigger squirter in it and went up 2 jet sizes in the primary.I also put a heavier secondary spring in it as well. Out of the box it ran great now it is close to perfect.
All I have for mods is a small towing cam in a 350 olds with LT Headers, and performer intake OH and the new Holley.
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Since you already have the RPM intake the Q-jet would be a hassle. The Edelbrock 1405 is performance tuned out of the box, the 1406 is tuned more for fuel mileage. If your going to run a Edelbrock carb buy a calibration kit #1479 or #1487. It has everything you need to tune the carb right. With the size cam you are running the 1406 would be a better choice and with the calibration kit you can adjust as needed. I've used Edelbrock for over 15 yrs. and never been sorry. Just don't skimp on the little pieces like linkage parts etc. They will cost you but they make all the difference in ease of installation.
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I talked to a guy at work today. He LOVES Edelbrock carbs, suggested me the 1406, just use more aggressive metering rods, he didn't remember the size then, step up to a .100 jet if it's still too lean in the primaries. and told me to drive it and enjoy it stating the 600 edelbrock is great for up to 400ci.
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the qjet was probaley 750cfm or bigger. i think the 750edelbrock but thats just my 2cents.
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So i called up Edelbrock Tech Support and spoke to a carburetor tech.... gave him the specs I have on here just I like gave you guys...expecting him to tell me a 1406...he tells me to use the 1412 800CFM! I was like WTH, I asked him why such a big carb. He was telling me with the vortec heads, the RPM Intake I have, and My cam's profile. It's very similar to their RPM package and the 800cfm is the carb that goes on it....
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The Quadrajet is the best street carb available.
Save your money and rebuild the Quadrajet and buy a wideband instead to set it up.
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That would be a wideband O2 sensor.
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An 800 is WAY to big for your app. Even with the extra flow of your intake and heads, I wouldn't go any bigger than a 650. I would go with the 600 personally. A smaller carb will give you a bit better mileage too I bet. I run a 600 on my 350 with performer intake and ported steel heads, and it is great. Good throttle response, and not half bad mileage.
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Dude. Your set-up would be perfect with the 670cfm holley. If you go with the 800 you will be returning it the very next day.
670 cfm is perfect. Holley carbs have there pros and cons. Biggest Pro. Parts are always just down the street at the parts store.