Is a pair of holley 350 2barrels setup with progressive throttle ok for a 302 with headers, intake and mild cam, maybe some head port&polishing?
Brett

 

Way too much carbureation, in my opinion. 600cfm is more than enough for a mild build. You aren't Stevie Ray Vaughn, so what do you need with double trouble.

 

Would they be ok if I jetted them lightly?
Brett

 

You have to jet them so it runs right. You go a little on the lean side, but too lean will result in misfire, surging, flat spots, and sometimes flat out bogs.

What kind of manifold are you putting them on?

 

like to see the manifold.... got any pics

 

I don't have a mainfold yet, I'm trying to find out if I could buy or make some adapters to use on a dual 4bbl intake(thinking Edelbrock f-28 dual quad), I asked to find out if it would work, and not be a gas hog. If I jetted as lean as I could get it, and put it on progressive throttle linkage, would it do ok on mpg compared to a 500-600cfm 4bbl?
Brett

 

lot of work... just get a rpm intake and a 600cfm 4V

 

found some good read for ya

http://www.gerlecreek.com/documents/tptechnical.htm

 

I've heard of the tri-power before, but have never seen one. Would I get better mpg with a 600cfm 4v?
Brett

 

They have smaller primaries... ventura??? (sp) just stay out of the secondaries...and get the one with the elec. choke... they are geared for MPG and not performance

 

Would a 500 or 550 be big enough?
Brett

 

Holley flow tests 2bbl carbs with 3.0"Hg and 4 bbl carbs at 1.5"Hg so you can't directly compare them, two 300 cfm 2bbl carbs don't flow the same as one 600 cfm 4 bbl.There is a correction factor of 1.41 so a 350 cfm 2bbl carb would only be about 250 cfm when run in a pair.

 

I'm not too familiar with carbs, so could you explain a little more.
Brett

 

When they flow test a carburetor they need a difference in pressure from one side to the other or else it flows zero,this is measured in inches of Mercury.Two barrel carbs are flow rated at 3.0'" Mercury(Hg) and 4 bbl carbs are rated at 1.5"Hg.This means that if you had a vertical tube full of Mercury and applied the same amount of suction the Mercury would move 1.5" or 3".If you apply more suction you get more flow so in order to standardize things Holley uses 1.5" to measure 4bbl carbs and 3.0" for 2bbls, I believe they did this as the original flow benches they were using could not produce 3.0"Hg with a 4 bbl carb.So a 750 cfm Holley 4bbl only flows 750cfm when a pressure difference of 1.5"Hg is applied across it, if you stuck it on a flow bench with 3.0"Hg it would flow around 1000 cfm as there is much more suction.A Holley 350cfm 2bbl only flows 350cfm when 3.0"Hg is applied across it which is twice as much pressure difference as the 4bbl.So if you want to compare the flow ratings of two carbs you also need to know how much suction or pressure was used to determine that flow rating as well.

 

Thanks to being schooled by idfergusson, I'll retract my earlier opinion about the 2-2 set-up being too much carb, but I still think they are double trouble. The 550 might work.