Multiple Stromberg 97s on a Hemi!

Stromberg 97 4x2

Four 97s on a Hemi!

Multiple 97s on your hot rod motor? Sounds good, doesn’t it? Check out this great Stromberg feature on the HOT ROD website! Written by Barry Kluczyk, we follow Bill Jagenow, at Detroit-area Brothers Custom Automotive, as he installs and tunes four new Genuine 97s on a DeSoto 291 Hemi under the hood of a 1940 Ford.


As Bill says, “It’s very easy to overdo it with a multi-carb setup. The 291 Hemi is not a large-displacement engine for four carburetors, so we’re backing off the fuel supply a little. We’ll start with the ‘41s’ and see how it goes after the engine is running again. We’ll check the plugs and make adjustments as necessary, but experience suggests they’ll be the right jets.” Just one thing. Bill recommends fuel pressure at 3.5psi. We prefer 2.5psi.

According to HOT ROD, “With the air horns back in place, the soldier-like formation of the quartet of Stromberg 97s looks strong. Because there are so many connections on a multi-carb setup, it’s important to check for fuel leaks and the tightness of carb mounts after the first few drives, but with the synced carbs all performing strongly, the driving experience of the Hemified 1940 has never been more fun or responsive.

Big thanks to Barry and Bill, of course. If you want to speak to Bill about Stromberg for your own hot rod, you can contact Brothers Custom on (248) 760-0700 or email at

Click here to read the whole feature.

BIG97 hits over 300cfm flow!

We have been testing our BIG97 carbs recently to see how much cfm we can get out of a modified carburetor, with our consultant Norm Schenck at Competition Fuel Systems in Michigan. The vertical manometer shows the vacuum pulling air through the carb – 20.4″ H2O, which is 1.5″Hg. The handle on the front of the flowbench, below the carb, is set on the 400cfm scale. The inclined manometer shows the volume of air going through the carb as a percentage of that 400cfm scale. In this case, 77% of 400 is 308 cfm. There is a probe inside the 5″ cylinder below the carb, with a small correction factor that makes the airflow correct in term of the Superflow flow calibration plate. Applying that correction factor brings the flow to 300.5 cfm, though what looks like a regular Stromberg 97!!

If you’re planning a big engine build and want some serious cfm capability, contact Norm at Competition Fuel Systems – email

BIG97 Tri-Power Installation video

Want to know more about BIG97 Tri-Power installation? Watch Bob ‘Bleed’ Merkt modify his Chevy intake manifold and install the carburetors, linkage and fuel line on his 1932 Ford Panel. The Stromberg BIG97 Tri-Power base castings may have the same external dimensions as a regular 97, but on the inside you’ll find bigger, offset throttle bores with flared exit cones to increase airflow capability and improve air pressure recovery. The intake manifold modifications recommended here (click this link for a print-out) enhance that effect, adding even more potential to your BIG97 Tri-power.  Another great video, awesomely directed and filmed by Piero DeLuca.


Stromberg BIG97 and 97 in Jan 2016 Street Rodder

Stromberg BIG97

BIG97 in Street Rodder

Stromberg 97 carburetors ( regular and BIG97 ) have gained some superb coverage in a major feature in January 2016 Street Rodder. It’s all about flathead Ford intake manifolds. Navarro, Edelbrock, Sharp, Offenhauser and more (all of which can work with the BIG97, of course). Written by Ron Ceridono with help from Kev Elliott and Mike Herman from H&H Flatheads, it’s also available online. You might find the online version a little easier to read. Click here to check it out! Here’s a couple of excerpts:

“Thanks to Mike Herman we were able to gather photos of the most popular intake options H&H currently offers for early (1932 to 1948) and late (1949 to 1953) Flatheads. While the manifolds look similar there are significant differences. The positions of the carburetors on two-two manifolds vary and as a result some require moving the generator, others don’t (manifolds that accommodate the generator are often called regular dual, while those with the carbs further apart are usually referred as super dual). By spreading the carburetors further apart they have a straighter shot into the ports and fuel distribution is improved but relocating the generator requires a head-mounted bracket. Some manifolds are equipped with exhaust heat, others aren’t. In cool locales with today’s fuel exhaust heat can help driveability, in hot climates it’s not normally necessary. All the manifolds shown here accept the stock-style fuel pump stand and the oil filler/road draft tube for 1949 to 1953 applications. Another difference is the number of bolts used to secure the manifold. Due to the shape of the runners, in some cases, the number of bolts has been reduced. On the other hand, in some cases, there are more holes in the manifold in the block, but in either case it’s not a problem.

Although all the manifolds shown are good, some manifolds may perform better than others with a given engine combination. The best bet to resolve that issue is to deal with an expert on the subject like Mike Herman.

Stromberg now offers a larger version of the 97. Completely reworked internally, they flow 250 cfm, compared to the original’s 165 cfm.”


1-1 The Stromberg 97 carb with vacuum port


Thought it was about time we wrote something on the almost mythical Stromberg 97 1-1 model. You don’t see many of them because they were never a stock OE fitment on any new Ford cars. Instead they were an aftermarket fit (to replace the Ford/Holley carburetor) for 1949 to ’53 Ford cars and small trucks with the infamous Load-o-matic distributor.

So how do we ID them, and why are they special? First off, note the writing on the side of the float bowl. By the time these came out, Stromberg had moved from South Bend, Indiana, to Elmira, NY. To the left of that, under where the kicker linkage goes, you will see a small 1-1 mark just above the circle with the 31/32 mark. The being a different bowl casting, the Stromberg part number – P-20671 – just above the 31/32, is changed from the P-21951 on regular 97s. In case you wondered, 31/32 is the size of the venturi in inches. 0.96875 inches, which is why it’s called the 97. There is another 1-1 mark under the bowl – check out the pictures.

While this example has the vacuum port, not all Elmira or 1-1 carbs have it. Most of these late model 97s also used this weird looking ‘W’ or ‘arrow head’ base. I have no idea why they changed to this ugly lower flange shape, but it’s interesting that many an aftermarket (i.e. 1950’s) intake manifold has the same shape mounting platform. Back then, you could buy 97s brand new, and this is what they came with, so I guess it makes sense.

Something else 1-1 carbs share is the ‘extra’ off-idle transition circuit. 97s were traditionally known for a slight off-idle hesitation. These two extra fuel circuits – you can see the small brass nozzles in the base/throttle body casting in the pictures – were the fix. They needed a brass jet because, by then, the throttle plate is moving away from the throttle bore wall and the exit for the fuel needed to be close to the edge of the plate to generate the correct local vacuum signal to pull the fuel out. That’s why the tips are angled to match the arc of the plate as it comes up. Eagle eyed readers will also notice that the plugs in the back of the base are extra large – needed because those little brass jets were inserted though those holes in the back of the casting into a seat on the opposite wall.

OK, let’s talk about the important part. As we said, the 1949-’53 Ford flatheads used the new Load-O-matic distributor, which, amongst its many failings, is the fact that it has no mechanical advance mechanism. It’s ALL vacuum controlled advance. So its compatible carburetor has to provide the right vacuum conditions all of the time. This is why a typical ‘ported vacuum’ carburetor like the Stromberg 9510A-VP, for example, cannot work with the Load-o-matic distributor.

The key to this carb’s compatibility with the Load-o-matic is the fact that it takes vacuum from two different places inside the venturi and throttle body. One is what you’d term the usual ‘ported vacuum’ position in the throttle body, just level with the transition ports, which is above the throttle plates at idle. The other is a small brass jet pressed into the bowl casting right at the narrowest venturi point. It had to be inserted from the outside, of course, hence the extra boss and lead plug on the outside of the bowl casting, just beneath the kicker linkage on the side. The fat extra boss on the side of the base is where you connect your distributor vacuum tube of course. The fact that the actual vacuum hole is tiny, almost hidden in the bottom of the huge fitting thread is indicative of the ‘hokeyness’ of the whole set-up.