When it’s time to transition your street car to track use only, what are the ways to increase power and reliability without any constraints of a street fuel delivery system? Here at Street Muscle, we have a car that was seeing more time on the dragstrip than the asphalt, so we decided to upgrade the fuel delivery system to take advantage of the car’s less restrictive racing environment. The existing carb was on its last leg anyway, so we gave our friends at PROFORM Parts a call to see what they had up their sleeve to help us reach our goal.

From Street/Strip To Strip/Street

We were in luck as PROFORM has refreshed its lineup of Race Series carburetors. They went back to the drawing board and completely redesigned the main body and fuel bowls with the latest features to ensure that PROFORM maintains its place at the forefront of carburetion, married with the value that customers have come to expect.

Starting with the heart of the carburetor, the new Main Body design features a contoured leading edge on the venturi, which smooths the inbound air prior to mixing with the fuel. The billet-aluminum metering blocks and aluminum fuel bowls have a new fuel baffle design that integrates with the fuel bowl float for better fuel control. The metering blocks are fully adjustable. The aluminum fuel bowls, with sight glass windows and billet fittings, are a new design that has enhanced fuel baffles, optimized for better fuel control, and a lower fuel delivery ramp that reduces fuel turbulence. Baseplates have slabbed throttle shafts standard, and each Race Series carb is hand-assembled and dyno-tested in the USA by racers, for racers.

The Race Series carbs also include adjustable screw-in air bleeds and Torx head squirters. The new billet aluminum throttle base plate is fully adjustable for fine-tuning, and won’t warp. If you are running a Blue Oval car, the throttle lever is compatible with Ford kick-down bracketry, and the secondary opening rate can be adjusted with a linkage kit which is sold separately.

The 750 is also available with a protective Black Teflon coating that gives great corrosion resistance and a cool high-performance look. It’s also resistant to almost all underhood chemicals, fuel, and moisture.

We like what we saw, so we decided to go with the company’s new Race Series 750 cfm Carburetor #67200 to crown our trusty 383ci small-block Chevy stroker motor. We especially like that the Race Series carb has contoured venturis and new two-step-down-leg boosters. Down-leg boosters are better for fuel delivery at mid-range to higher speeds, which makes them great for drag racing. Carburetors with down-leg boosters also tend to be a little more friendly on the wallet than their billet annular cousins.

We took delivery of our 750 Race Series carb and got to work installing the new unit. First things first, we disconnected the battery and throttle linkage and then broke the fuel and vacuum lines free. Then we unbolted the old carb and set it aside. The installation took roughly 1-2 hours. After we cleaned up the site, we set the new carburetor on the intake manifold and bolted it down. Then we reconnected the battery, throttle linkage, fuel lines, and vacuum booster line. No need to wire up an electric choke because the Race Series design doesn’t have one. This does not require a high mechanical skill level to accomplish and utilizes common automotive tools as well.

Easy Installation

We love to tinker, and thank goodness the days of nonadjustable pressed-in fittings are over. Adjustable parts are now a standard feature allowing you to tailor the carb to your application. The included non-stick gaskets allow for quick disassembly of the fuel bowls and metering blocks to access the power valves, and jets. You can dial in the fuel curve, along with the rest of the carburetor parameters to your exact standards.

Flipping the new carb over gives us a look at the billet throttle baseplate. Aside from racy good looks, the baseplate provides power valve blowout protection and slip-link mechanical secondary linkage.

The carburetor’s linkage was similar to that of our previous carb, so when it came time to reconnect our throttle and transmission kick-down cables, we didn’t need to do anything different.

A view from above shows off the down leg boosters that will provide us with the high-RPM grunt we need at the strip.

The Race Series 750 carb comes with plugs and inverted flare fittings on both fuel bowls, which is great if you’re running a stock dual-feed fuel line, otherwise, users need to provide their own fittings if they’re running AN lines and fittings like us.

The biggest challenge of the installation was finding the AN adaptor fitting we needed to taper down to a -6 at our local parts house. It’s a 7/8-20 to -6AN, by the way. 

The final step in the installation was connecting our fuel lines to both front and rear inlet fittings and connecting our vacuum lines at the rear of the baseplate.

Driving Impressions

After installing the new PROFORM Race Series 750 carburetor, our small-block stroker drives great. While some other carbs on the market might provide us with a bit more “streetability” in terms of low-RPM responsiveness, the Race Series carb does exactly what we need it to do as we transition this car to a track day terror. Even though we are using the 750 for dragstrip use, it can be used for street applications as well.

Where it really shines is when we take it into the higher rev range. The miles we’ve put on it since the installation has consisted of putting around town a bit to see how its street manners are, and they’re perfectly fine. Additionally, we’ve made a lot of freeway onramp pulls, and it runs like a bat out of hell.

We haven’t had a chance to get the car down to the dragstrip with the new PROFORM setup, but when we do, we’ll bring you an update with all the details. Stay tuned to Street Muscle for all the news.

PROFORM Parts (Specialty Auto Parts USA, Inc.) based in Warren, Michigan, is a leader in the high-performance automotive aftermarket by engineering and manufacturing creative products from smart concepts. The goal is to provide the performance enthusiast with innovation, quality, and affordability in all their products – giving the customer maximum value. With dozens of patents, thousands of SKUs, and millions of satisfied customers, PROFORM has brought innovation, quality, and affordability to enthusiasts for over 30 years. Each PROFORM part is designed to deliver maximum performance, value, and style. Go here for their full portfolio of automotive parts.