I have a 78' Chevy Malibu with a 350 engine. I currently have a 670 Carb but it doesn't seem too good. I want to purchase a Holley 650 or 750 carb. Which Carb is the best to get? Is a 750 carb needed for a modified 350? Because I was told 750 carbs burn too much gas. Whats the advantage between the 650 and 750 carb?
Any advice is welcome.
Reply asap. Thanks.

What has been done to the engine, what gearing what kind of convertor or std, all these issues are important in choosing a carb.

I just want street performance. Currently I don't have much modifications done to the car. I just have 3.73 Posi Rear, Im going to buy Headers, Exhaust system & Cam Gears and a few others parts nothin major.

My problem is the car doesn't idle right, Im wondering if the 750 Holley Carb to much for what I have done to my car? Whats the best Carb for my setup?

Do I need Cam Gears to help the car idle better? What could be the problem?

The 750 is way too large for a stock 350, 600-650 cfm or a stock quadrajet is plenty, the rough idle may not be the size of the carb as much as a vacuum leak idle or adjustment and so on.

The 750 is way too large for a stock 350, 600-650 cfm or a stock quadrajet is plenty, the rough idle may not be the size of the carb as much as a vacuum leak idle or adjustment and so on.

I will buy a Holley 650. Is a 650 Double Pumper the best carb to get? Im going to order the 650 from this site (Jegs High Performance): http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=15843 (http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=15843) . Is this the right 650 to buy for my 78' Malibu? Also I'm wondering whats the best Cam Gears to buy? Thanks alot!

Personally, I would go with a Carter AFB or an AFB clone such as an Edelbrock Performer. These give less problems overall than the Holley carbs do. I've got one with almost 200,000 miles on it with only one rebuild during that time (at the 160k mark).

Personally, I would go with a Carter AFB or an AFB clone such as an Edelbrock Performer. These give less problems overall than the Holley carbs do. I've got one with almost 200,000 miles on it with only one rebuild during that time (at the 160k mark).
Agreed on th AFB/Edlebrock carbs, ran them on my crossram 64 Belvedere for 25 years, no issues.

Small chev can only flow 666cfm,as for the double sqirter,no.Vac secondary with a spring change,but thats just me I guess.

I have been far removed from carb engines but I can tell you this. You have to buy a carb designed for the engine you are running it on. If the 350 is pretty stock I would talk to someone that know what carb is going to perform the best and with the best fuel economy in mind if that's what your looking for. These guys are right. A bigger carb will run crappy unless the engine can take that much fuel at one time. Pending on what 350 it is I would say you are putting out somewhere in 250hp to maybe 285hp if it's stock.