New Summit Brand 600 cfm 4bbl carb
 

I'm looking at replacing an old "emissions reverse idle style" circa mid 1970's Holley 4160 list 8004 for the new Summit 600 cfm 4bbl they have been advertising. (The Holley came with the engine..but is not really the right carburetor for it,IMO) I think this new Summit is based on the old Holley 4010 carb, which is a lot like the old ford 4100's, I believe. I will be bolting this to a 302, bored+40, with the Ford standard 4 bbl intake manifold and with 1969 351W heads. The only emissions control on this engine is a PCV . Has anyone tried this carburetor and do you like it?

Unless you love to constantly be "dicking" with your carb, I'd stay away from that piece of ****.

I used a couple of them when Holley sold them and they ran just fine. I would personally go with a 500 or 600 Edelbrock carb myself.

Thanks Lx!

That Holley I currently got runs lean on idle, (the reverse idle screws are turned in all the way rich....and it wants more. No vacuum leaks I can find anyway!) I could try swapping out the rear metering plate for one with the next larger size idle jets, but then what else I am going to have to play with to get it where it needs to be, so that's why I am thinking about going after this carb, and the price point is where I am comfortable. I would love a good 1.08 4100, but they go for big bucks. You mentioned Edlebrocks,I will look into those as well as I know many people really like them!

The annular boosters are a super design, as you say dating back to the 4100s. Have read of some improvements over the 4010, but they had good performance too. I am someday going to use a 4010 or 4011 on one of my projects.

Summit Carb
 

I have a 600cfm vacuum secondary Summit carb on a 78 Fairmont with a 302/auto mild cam, headers, free flowing exh, wieand hi rise intake. I really like this carb , great throttle response , good manners ,choke works great. Performance is excellent. Fuel milage on average is better now than with the 2bbl, unless you are on it. Overall I would buy another one , I tried my buddys 1850 Holly and it didn't work as nice , throttle responce was'nt as good and fuel milage was down--- wide open performance was similer.

Have A Good Day -- Hotwrench}>

For street I think the big draw back to Holley is gas mileage. Most Holley's no matter what you do to them never seem to get as good of mileage as other brands. I have owned in resent years a Holley 4160 on a 460 & 4175 Spread bore on a 360 Dodge. They produce power but at the cost of mileage. With gas around $4/gal I always think in that area also. The carb I think is one of the best overall is the Q-Jet. But remember I was GM schooled on working on them. In the 70s I was a dealership line mechanic & tune up & smog was my job.

My thinking, without having used either, is that the Holley 4010 or new Summit look a like may be better in the mileage arena, due to the efficiency of the annular boosters. Mileage is important to most of us I think. The hot rodder with a pair of four barrels and rad cam can say it doesnt mean anything, but then their car/truck is only seen once a month for short outings (only observations).

Could not agree more with you.

Fuel milage
 

I run my Fairmont every day with the Summit carb, Its my daily driver. I t gets better milage with the Summit carb than it did with the stock 2bbl. I drive with the use of a vacuum gage, I try to keep the highest vacuum reading posible. When I pound on it of course milage suffers but this is to be expected. I get some more money rounded up I'm going to try one on my T Bird with a 390. I think if you tried one you would like it.

Have A Great Day --- Hotwrench}>

I think the metering rod set-up on the AFB/Edelbrock carbs, as well as Q-Jets on a GM, help with the part throttle MPG's because they are two stage rods for part throttle economy and can run leaner where as the Holley is dependent on the jet size and whether the powervalve is open or closed.
Either is a good choice. I like not having any gaskets below the fuel level which can leak. Especially on a vehicle that sits a lot.

Installed a Holley 1850 (4160) 600 cfm, probly little more than needed, bout 12yrs. ago on a 67 and 70 302ci. The intake is a Edlebrock dual plane and I installed a ported spacer. Couple yrs. ago started experiencing carb problems and took it in to exchange for new Holley and the machanic suggested rather than replace I should rebuild the 1850. Not that knowledgeable when it comes to carbs, agree for fuel milage newer likely better but decided to try the rebuild kit, found it was not that difficult, fairly basic, and it has been running fine since.