Lightning Racing Carburetors

02/18/2026

Can anyone point out what’s wrong here? It is a BLP billet body but it was not assembled at all by BLP, but by another “Pro” carb shop…🤦‍♂️🤦‍♂️🤦‍♂️🤦‍♂️🤦‍♂️

03/16/2025

Congratulations to my brother Randy Whitener for his win at the index race Orlando this past weekend. Three races with a fresh engine he got down to 11 cars in Super Street at the Orlando divisional, 7 cars at the Gainesville divisional, and the win in Orlando.

03/16/2025

Congratulations to Steve Schumacher for getting his C/EA to run .719 under the index at the Gainesville divisional race. Of course that hurts his index a bit…

12/12/2024

Proper T-slot exposure

So I’m posting this to make everyone aware of the importance of proper t-slot exposure. I had the opportunity to help someone with a 4150 on a street pickup with a small block with a stick. The carb was an aftermarket billet 750, and fortunately he had an AFR gauge in it. He had tried several things, even had a different carb company help with tuning to no avail. His issue was it was on the rich side at idle, but getting into the transition circuit showed lean peaking the meter at 17 to 1 from off idle until the mains came in. We made idle feed changes, air bleed changes, nothing seemed to help. Then I had the aha moment, I opened the primary idle speed screw 1/2 turn, exposing more primary t-slot, brought the secondary down to lower idle speed back, and everything fell into place. Set the mixture for idle, light throttle O2’s fell into the 14-15 to 1 range. Too much air going through the rear blades made the primary transition too lean all the way until the mains started. Had I built the carb from scratch I would have set it, just overlooked it initially when messing with the calibration. This is a trick on a race engine to help with a stumble coming off idle, there are situations where no amount of squirter or pump shot will fix. And this would have been harder to figure without O2’s, or the experience. When rebuilding a carb always set primary t-slot exposure, and set idle speed with the secondary. Too many companies neglect the importance of proper idle/transition metering and T-slot size and exposure. It matters even on high end race engines.

10/12/2024

Importance of proper timing

So I see this come up fairly often where the carburetor is blamed for problems as a direct result of improper timing. Stock engine run fine with stock distributors because they have very mild cams, lower compression, and are calibrated specifically for those engine combinations. Small cams have higher vacuum at all loads and throttle positions, so the total timing required is low. When you make changes timing requirements change. Haters, bigger cams, different intakes… anything that changes will change timing needs. Camshafts are the main change, larger cams lower vacuum at all ranges, but is impacted most at idle. More initial timing maintaining the same or near total, and vacuum advance can be still useful until cam specs get around or over [email protected]. Lower vacuum does not atomize fuel as well, less early vaporization. This means the fuel will take more time to burn at the correct time for best power, more timing. And it changes as the engine sees different RPMs and loads. Higher loads generate more combustion heat, and require less timing. Higher overall engine temps require less timing, and usually a colder plug heat range. So before you condemn the carburetor make sure timing is optimal for the specific engine needs. Understand too that running pump gas on a performance engine can limit the timing to less than ideal. It may require the carb to be on the rich side to help keep combustion temps down to prevent detonation or preignition.

Most distributors have limited tuning capabilities, especially with the vacuum advance. My suggestion is funds afford is to look at the Progression Ignition distributors. They use a map sensor for vacuum, and use a Bluetooth app to tune timing amount added and at what vacuum points timing is added or subtracted. Mechanical timing curves are based on RPM, and can be easily changed for the amount and when timing is added.

10/10/2024

So I did the drawing for this last year, finally broke down and bought a new printer. This was made out of PLA to test on the flow bench, both airflow and booster signal compared to the factory sleeves. All goes well I’ll make them out of Carbon infused Nylon to test at the track. Venturi sizes will be flexible.

10/02/2024

I don’t post a lot, this is a newer Dominator style carb I have available. It uses a separate base similar to a 4150, threaded stake tubes to make booster swapping easy. Testing with different size skirts takes a few minutes to do. Changing fuels is easier as well, gas boosters out, E85 or methanol in, swap metering blocks and air bleeds and it’s ready to go.

05/16/2024

There are some that have no business building carbs. The body is nice, a CNC machined part from BLP. The boosters were installed angled down, the end of the booster ring about .030-.040” down from the inner part of the ring. I don’t care if you ever buy anything from me, avoids these. There are plenty of quality companies out there.

04/17/2024

It’s about time, Pro Comp and Speedmaster need to be shut down to sell anything in the United States. They aren’t the only ones, and there are those that steal ideas from others and put their own names on patents.

In this video Jay Robarge of Broader Performance will demonstrate a classic example of large corporations that exploit and counterfeit products of small busi...

04/09/2024

I decided to retest the booster inserts I designed and have made for my use. It is a stock old style Holley 9375 1050. The cast insert is the stock 8 hole .500 center, the black my billet .610 insert. When designing I modified the fuel channel to ensure the maximum fuel channel size that would still work correctly in a 4150 banjo. It’s been tested to well over 600 HP on methanol, and would support at least 1200 HP on gas. It was also designed with airflow and signal in mind. On this body with a stock insert a single hole flows 320 CFM. Times 4 holes it is approximately 1280 CFM at 20.45” of water, standard for measuring a 4 barrel carb. Hot swapping the booster nets a 5 CFM gain on a single hole, and a 1.3” drop in depression. This reduces HP losses from pumping losses. Bringing the depression back to 20.45 nets a whopping 19 CFM gain per hole, bringing total airflow to approximately 1356 CFM. That’s a 76 CFM gain, on a running engine the overall airflow will pick up about 10 CFM, reducing pumping losses, and still creating a signal well above a stock booster. At standard testing depression a stock booster has about 45-48” of signal, mine runs over the max reading of my digital manometer which is 76”. I estimate it’s just above 80”. So many carb companies try to use emulsion to atomize fuel better, at the expense of the fuel curve. Some box carbs have so much emulsion and main air bleed that in some higher HP engines it can’t flow enough fuel, over rich at the bottom, too lean at the top. I chose instead to make the booster do the job it was designed to do, but do it better. And use emulsion to set a proper fuel curve, what it was meant to do.

01/31/2024

My latest project. It’s a 1981 Z28, I need a car that I can drive on the street with some of the carbs I build for testing purposes. And still be a viable backup vehicle, it needs a few things fixed but it runs and drives. Eventually a paint job.

10/15/2023

Never take anything for granted. I was sent this carb because didn’t idle right. Go thru, freshen, recalibrate. Still didn’t idle. Seems the main body casting was never drilled all the way thru to the idle channel leading to the idle discharge ports.. on all 4. It’s going to idle now!