Carbureted LSX forum - lq4 build carb size?
02-26-2012, 03:17 PM
hey guys. i finally got most of my parts to get my lq4 6.0 running thanks to tax return! ($8100:chug:) i still need a ls3/l92 victor jr intake, msd 6010 box and a carb. thats what i need help on. what carb should i run? more like what size. ive been lookin into the quick fuel carbs, they seem good, but are they really? my engine has factory bore/stroke but has ls2 pistons and rods, ls3 heads, and a decent cam. 234/250 @.050 .628/.624 lift intake/exhaust 112+4 lsa (i know its not perfect for carb but it should work ok?). slp built th400 with 3600 rpm stall and 3.73 gears. the truck weighs about 2600 lbs im guessing and im buildin this to drag race and spin some cookies (no joke). i just really want a vehicle to lay some rubber on the road and turn a good time in our local 1/8th mile track. i wanna give the most info i can... i really need help gettin a carb and gettin this setup done. anyone have any info on a good carb and also a good carb size for my engine combo? this is what i was lookin at but idk if 750 is too small and 1050 is too big? http://www.quickfueltechnology.com/carburetors-qfx-series/ any info will be great!
02-26-2012, 06:05 PM
Holley 4150 950cfm is what i have. Id rather have too much fuel then not enough.
02-26-2012, 06:32 PM
is the cfm the fuel flow or air flow? i thought fuel flow was in the jets and too much air would make it sluggish down low? anyone wanna chime in?
02-26-2012, 07:05 PM
I run a 750 pro form, it might be roughly 800 cfm, works great for me, but if i was treating my LQ4 as a drag car, i would have a 950 or so.
02-26-2012, 10:45 PM
got a quote and a custom spec carb from pro systems. they recommend 1100 cfm in their sv1 series, but i cant justify $1250 for a carb alone.... i was hopin for more in the 800 ish range.. anyone have any other info theyd like to share? i do like the idea of havin a carb specd for my setup so its basically take out of the box and run tho.
Pop N Wood
02-27-2012, 06:55 AM
Quick fuel definitely makes some good carbs. I would buy one if I didn't already have a Holley. Holley HP carbs are also quite good and from what people post on here seem to work well with an LS and single plane intake.
A 750 is probably the most common sized carb used by people with a 5.7L or larger. With your heads/cam and intended use you could probably go larger. Keep in mind that getting the part throttle response tuned just right is more difficult with a larger carb.
02-27-2012, 11:08 AM
with the larger heads and cam size look into the 850-950 cfm range. the smaller of the two will be more docile in street trim and won't give up too much on the strip. the sv1 is a fine piece and the throttle response is unreal. the cost is just a product of alot of r&d that went into it. call patrick back and tell him the sv is nice but you cant swing the bill. tell himm your budget annd see what he can do......
02-27-2012, 06:53 PM
thanks for all the help so far. ill get ahold of them and see what else if not them ill get ahold of quick fuel and see what they say (ive heard they are basically the "same" or somethin) i just hope this thing runs pretty well. hopefully better than the 330 ish hp 305 sbc i had in the truck before.. although the wife did say i can get the sv1 cuz shed rather me spend the money and do it right than hear me bitch about how it could have been better gosh i love this girl lol.
02-27-2012, 08:02 PM
I got a LQ4 and race and street drive I have a APD 750....
02-28-2012, 04:05 PM
If you need I can hook you up on Proform and Quickfuel Carbs as well as Edelbrock Manifolds ;)
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