I am sure you would be happy with the 500 on the 292 also. Smaller Venturi’s bring a better vacuum signal along with annular discharge boosters will increase bottom end and work best where we all drive our cars. My engine rarely sees 3000 rpm and that’s in second gear on an on-ramp. Even at highway speeds of 70-75 I’m at 24-2500 rpm. I’ve always used phenolic spacers under my carbs. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

With my Summit Gift Certificate from Fast Fords and the Y Block Shootout, I ordered one of these carbs as well. However, I went with the 500 cfm version. I will check through things on my 292 and then probably save it for my 272 I have in the shop in North Carolina. I do recall that the 500 cfm Edelbrock I had on the 292 before switching to the Holley was prone to heat soak, the Holley not so much. It does look like it is easier to tune the Summit carbs than the Holley's due to the fuel bowls being integrated into the main body. I am forever going through the fiber washers for the 4 bolts that secure the bowl to the base, and at times going through the metering block gaskets is a chore. 

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

I have a Quick Fuel 450 CFM that I bought from Summit, works great on my 56 Victoria 292ci and gets decent fuel milage also it's new not rebuilt.I had intended to install 2x 4s but changed my mind so I still have one new in the box I would sell if you are interested just pm me

To all the Great Y blocker who replied with great helpful information I say Thank You, but I have to confess I am at the bottom of the pole when it come to my old Y block!  My confession is that I overlooked the basic. It turned out that it was the distributor cap had hair line cracks. I look at it many times but not till I took a photo and enlarge it did I see them.  Had a new cap on shelve put it on and it now runs like a top. I can't tell you all that I put so much blame om the Summit M08600vs carb.  I can now say that that was a great choice. and will contact Summit to apologize to support people.  Old age is the only thing I can maybe blame.  Thanks again you all are great, and the group is very helpful.  Keep it up. 

I have installed the Street Demon 625 carbs on hopped up Y engines and like RB says, they do perform very well while also providing excellent fuel economy.  These carbs are available as either 625 or 750 cfm versions but for most Y engines, the 625 version is expected to be adequate for most applications. Those smaller primary bores do give enhanced low-end characteristics while also improving the atomization of the fuel for economy purposes.  The Street Demon carbs are available with either aluminum or composite plastic fuel bowls.  To date I have used only the carburetors with the composite plastic fuel bows as those do keep the fuel cooler and reduces the chances for any ‘heat soak’ that may be present.

These carbs are considered being three-barrel carburetors but unlike the older Holley three barrel carbs from the Sixties and Seventies, the Street Demon incorporates what is called a ‘Goggle’ valve for the secondary throttle blades.  While those older Holley three-barrel carbs required a slot in the primary divider in the dual plane intake manifolds, the ‘Goggle’ valve does not require that slot or similar modification to allow the secondary throttle blade to open freely.

While the Street Demon carbs have a very clean look to them as a result of no exposed screws on their tops, this feature does require the carburetor to be removed from the engine for any jetting changes.  While the supplied jetting is reasonably close out of the box, jet and/or metering rod changes will require that the carburetor be disassembled by turning it upside down to access the necessary screws.  The primary jets and metering rods for the Street Demon carbs are specific to those carbs and not interchangeable with other carbs.  But once jetted to your particular requirements, the Street Demon carbs are both good performers and trouble free.

Here are some pics.
  

  

  

Lorena, Texas (South of Waco)

I have a Holley 1848-1 465 CFM carburetor on my .060 over 292.  My engine has similar modifications to yours and is street driven. I chose this carburetor for a number of reasons.   I like the original look.  This carburetor is almost identical to the carb used on 1957 D code 312s. I am familiar with Holley carbs as I have been using them since I got my license in 1963. They are easy to tune, parts are available and they run great.  The other reason is this carb tested near the top of Ted Eaton's Y-Block dyno testing.  This did not surprise me as I am very pleased with it's performance.  A few other comments.  Throttle response is fantastic. This small 4V works perfect on a 292. I am running the stock jetting and secondary springs. My only modification was to install a manual choke.  My plugs are light tan and never foul.  Many of my friends run Summit carbs with good results.  I like the way my Holley looks and performs.

I like the idea of smaller primaries for better throttle response at lower rpm and increased mpg. The Street Demon, however, didn't perform as well as other carburetors tested (including Summit's) on an episode of Engine Masters, but keep in mind that their focus is on max torque and horsepower, which is not necessarily the best indicator of how a carburetor will perform at various rpm on the street. Testing an engine on a dyno, under ideal conditions, is not a fair comparison.

Every modern 4-barrel carburetor I've looked at has a manifold-base-to-air-cleaner-base height of 3.25-in. A summit 14" drop-base air cleaner/w 3-inch element provides enough hood clearance for my Street Avenger 570 carburetor and a 1/2" carburetor spacer on my 55 Tbird. If you have a truck/full-size car, hood clearance shouldn't be a problem. If I remove the spacer, I have just enough hood clearance for a 14" oval air cleaner/w 2" element. The oval air cleaners do not have a drop base. The drop-base air cleaner, to an extent, hides the carburetor; whereas, the oval air cleaner sits on top of the carburetor. 

By the way, there's nothing fancy about the Summit air cleaner, but I paid $29. It's a chrome, open-air sheet-metal air cleaner/w no logo (which I like). If you experiment with different element heights, you need to allow for sufficient clearance between the float-bowl vents and the air-cleaner lid, regardless of carburetor/air cleaner brand/style. Using any less than a 3" element on the Summit air cleaner put the lid too close to the bowl vents. The oval air cleaner's 2" element is not a problem.  

I have tried Summit,Ebock, and latest is the Demon 600 street carb from Holley  I like the demon the best.. great throttle response good idle and it gets better mileage than the other 2. It has small primaries which give the throttle response and mileage.. I bought mine direct from Holley as a refurb for cheap, but I see now they are within a few bucks of the other offerings.. I highly recommend them.. Mine was great out of the box. My motor is a standard 292 with Joe heads and a 312 intake and headers.. Smallish cam. 1800 stall converter and stock gears. 

From a previous thread where I posted the following:


http://forums.y-blocksforever.com/FindPost161256.aspx

The Summit carbs do use the same fuel needle seats, jets, and power valves as the standard fare 4150 and 4160 Holley carburetors.  That particular line of carbs incorporates annular discharge nozzles for the fuel which gives improved atomization of the air/fuel mixture as it enters the air stream.  Servicing the carbs is relatively easy as the top of the carburetor is removed to access the jets.  The fuel reservoirs on those carbs are amply sized thus allowing those carbs to sit for longer periods without the fuel levels being diminished as quickly due to evaporation.

I do have the Summit 500 cfm version on my ’55 Ford and while it is a good driver, that carburetor is still undersized for a lightly warmed over 272.  For most stock Ford Y applications, the 600 cfm version would be a good all around choice.  For any Y engines with upgraded camshafts, larger valved heads, improved exhaust, and the other typical performance mods, the 750 Summit carburetor is my carb of choice.  The 600 and 750 versions are jetted very close as received and typically may only require a slight fuel mixture adjustment after setting the idle speed.
  

Lorena, Texas (South of Waco)