which carb??

[Lit549]

I'm looking at a quick fuel 680 hotrod series with vac secondary, I called them and they reco.mended this carb for my setup but it sounds too big to me.I called asking about the slayer series 600 vs and he said the 680 would be better cause the 600 was mainly for stock and mildly built engines..Well mine  is a mild engine , it's a 10:1 355 with a comp xr270hr roller cam with 1.6 rockers it's like 528-535 lift and 110 ls.It in a 85 c10 stock converter and 3.08 gears.I was also looking at a 650vs holley , which would best for a street truck? It has a 600 Eddie on it now and Peters out about 4000 rpm on, I think it's a little lean under power, but I hate the carb..what would you buy??

[Irish_Alley]

570 is about stock/mid numbers
http://www.summitracing.com/expertadviceandnews/calcsandtools/cfm-calculator
i dont know a whole lot about carbs but i would get another professional opinion from another company and see what they say. i know ive always ran 600-650 on my engines. they're not built still stock compression and they've always been rich

[rich weyand]

You could properly tune the Edelbrock and see where you get.  No untuned carb will outperform a properly tuned carb, no matter what the brand.  If you are not willing to properly tune a carb, just throwing something else on there won't help.  You're just throwing your money away.

[Lit549]

You could properly tune the Edelbrock and see where you get.  No untuned carb will outperform a properly tuned carb, no matter what the brand.  If you are not willing to properly tune a carb, just throwing something else on there won't help.  You're just throwing your money away.

Oh its properly tuned , just wron carb for this engine..It Peters out at about 4k on, idles like crap, and is choking my engine down..Time to go back to a holley platform, I just don't wanna over carb it..There is no way a edelbrock is better than a quick fuel-ever...One thing I hate is the "metered" vacuum leak at throttle shafts, who builds a carb with a vacuum leak built into it-edelbrock! BUT, back to the question; which would be best carb??

[Lit549]

570 is about stock/mid numbers
http://www.summitracing.com/expertadviceandnews/calcsandtools/cfm-calculator
i dont know a whole lot about carbs but i would get another professional opinion from another company and see what they say. i know ive always ran 600-650 on my engines. they're not built still stock compression and they've always been rich

Ya man that's why when he told me the 680 I thought man that's way to big! Maybe he's just trying to sell the more expensive carb?? I thought the slayer 600 would've been perfect?? I also called edelbrock and holley, edelbrock recommended the 650avs, holley said the holly 600 vs carb would be plenty?I may just let "Mr carburetor" build me a 650 holley vac secondary. He builds carbs for the vette clubs in dallas, Gas Monkey garage, and has some championship cars with his carbs..ha, decisions, decisions. .

[78BIG-TEN]

I have a 600 on my 350 and it performs really well.Truck pulls great through 6000 range.That being said I also have a 750 that I can swap out at any time.It took a lot of time getting the jetting right and quite frankly not much more in the way of performance .By the way both are HolleysBoth idled extremely rich and mixture screws did nothing for it.The reason was idle stop screw had primarys open past transfer slot.Drilled 1\8 hole in each primary blade and solved the problem.Just too much cam for stock settings.As soon as I get my speedo calibrated I will post some mileage numbers