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Old 07-27-2004, 11:19 PM
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Angry ARRRG what carb should i use!?

what carb should i use on the following build?

-I called holley and they told me a 650
-My mechanic tells me a 650 double pumper
-Edelbrock tells me a 650 Thunder AVS carb
-My bro tells me a 750 edelbrock

i have no idea what to go with.


-350 2 bolt main bored .040 (357ci)
-All ARP fasteners
-Holley 600 cfm rejetted (probably need a 700 huh?)
-Holley High Flow Mechanical Fuel Pump
-Edelbrock Performer Air Gap Intake
-Accel High Output Distributor
-MSD 8.5 Race Tailored Plug Wires
-MSD 6AL ignition
-Trick Flow Valve Covers
-Summit Aluminum Roller Rockers (1.5 on exhaust, 1.6 on intake)
-Dart 64cc Iron Eagle Heads
-Stainless Steel 2.05 intake and 1.60 exhaust valves
-Keith Black Flat Top Pistons
-10.5:1 Compression Ratio
-Cast Crank and Rods
-Comp 274XE Cam (.490 lift 236 duration) (.520 on intake with the 1.6 rocker)
-Clevite Bearings
-Double Roller Timing Chain
-Hedman Headers
-2.5" Dual Exhaust with no catalytic converters and Flowmaster 40 Series mufflers.
-Richmond 3.73 Rear end ratio
-Eaton Posi Differential
-Built 200-4R Transmission
-2500 stall
-Griffin 4 Core Aluminum Radiator
-B&M Transmission Cooler
-B&M Ratchet Shifter
-Front and Rear Sway bars

I am also going to get a Performer RPM intake, i hear a lot of good things about it.

on that topic, what exactally is the difference between the Performer and Performer RPM, i know the powerband is 1000 RPM higher but i know that cant make as much of a difference as i've heard. Are the runners bigger or polished?

Right now with this setup in an 1987 Monte SS (about 3600lbs race weight) i ran at the 1/4 mile and hit 14.7 at 88mph...then i found out my secondaries werent opening because the diapragm collapsed. i fixed it and i ran again but not at the track (i live on an air base with a closed runway so everyone messes around out there cause we measured out a 1/4 mile exactally.) now i hit 5000 RPM which comes out to about 108 mph (speedo only goes to 85) which i think is a mid to low 13. I dont think that is too bad for a small carb, will a bigger one make a big difference? if it will only cut a tenth or two off i dont think it is worth it (unless its that tenth or two that breaks me into the 12s).

Lastly i am burning kind of rich down low right now cause my mechanic put a power valve plug in but in turn hat to really up the jets. this is the only thing i didnt agree with, i never heard of pluging it before, but i didnt really say n e thing cause every other thing he did made a noticeable improvement. So if i put the power valve in and took the jets back down will it run better with better gas mileage, or will i loose power?

thanks for the help

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Old 07-27-2004, 11:33 PM
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Quadrajet

Or Edelbrock somewhere in the range of 700-750cfm.

I dont like mechanical secondaries, something always seems to go wrong. Get a nice Edelbrock 795CFM Q-jet and you'll be more than happy. Plus most the tuning can be done real quick and only needs to be done once to get it right. Not fiddling with jetting here, just turning a few screws.
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Old 07-27-2004, 11:36 PM
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i really dont want to use a q-jet, i know they can be great but ive had nothing but probs with em...bad vibes lol
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Old 07-28-2004, 05:42 AM
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I would use a Holley 750 vac secondary (#3310).
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Old 07-28-2004, 06:04 AM
Technical Support Barry Grant
 
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What size carburetor to use?

Your combination is borderline between a 650 & 750 Vacuum Secondary carburetor. With a 2500 Stall speed you're going to get better drivability with a vacuum secondary carburetor vs. a mechanical secondary carburetor. There are pros & cons to both sizes it really depends on what you are looking for. The smaller carburetor will give you better throttle response, and acceleration with the gearing you're running in the rear end. The larger carburetor won't accelerate as quickly, but will pull stronger as your RPM increases. Actually ET there isn't going to be a lot of difference, it's mainly a matter of what you are looking for.
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Old 07-28-2004, 06:24 AM
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i think ill go with the 650 vac secondary then, i like having the nice response, any carb in particular? will it come good out of the box or will i have to change stuff?

now as i was asking in my original question, will this make a big/noticeable improvement?
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Old 07-28-2004, 09:41 AM
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Every carb has to be tunned out of the box for that specific engine, no carb is just a simple bolt on.

It can be a noticable difference if you tune it correctly. Having an O2 sensor is almost a must to get it perfect.
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Old 07-28-2004, 09:52 AM
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i hear a lot about O2 sensors, but i also hear a wideband is the only one that will really tell you where you are...and those are like 400 bucks!
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Old 07-30-2004, 08:44 AM
Technical Support Barry Grant
 
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O2 Sensor

You can get a wide band O2 from Innovate Motorsports for under $350. http://www.innovatemotorsports.com/
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Old 07-30-2004, 08:58 AM
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I personally would use either a 650 or 670 cfm with a 1"open spacer...or a 700.
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