Don Terrill’s Speed-Talk

The late models that will be running at Bristol are mandated to run carbs and are also 430 cubes vs napcars 358 so not much a comparison. I’ve never seen a ls engine pick up power going to carb and I’ve personally witnessed a handful on the dyno. What carburetors did you use? There can be big diffe...

A lot of Pro Mod racers have tried injection and gone back to carburetors.

We've worked with it for over 20 years and it has advantages and disadvantages. It'll produce more power than gas and less than methanol in most cases. Fuel system components need to be alcohol compatible if you want longevity. You have a lot less fuel consumption than with methanol, some cooling ad...

Sorry to see this and condolences to his family and friends. He seemed like a great guy with a lot of enthusiasm. His posts were enjoyable to read and he will be missed. From what he said in some of them I believe he's now in a better place.

Boiling fuel or picking up air will both act like that.

You might not have a vacuum assisted bypass valve like I described.

If it's an actual bypass valve the carburetor would be fed by the pump and the bypass is downstream creating a "dam" to build pressure. The vacuum helps to lift the diaphragm in the bypass so fp is lower at idle (high vacuum, no engine load) and the diaphragm is pushed down harder increasi...

Manifold vacuum is going to be higher at idle with no load than it is with the engine loaded and throttle open. All you need is manifold vacuum to make a vacuum assisted bypass work.

That should always be the first thing tried. It saves a lot of time.

Is this for Dirtcar or track rules that use theirs as a template? Do you have any spacer on it between the carb and intake? We've built carburetors for and worked with the 602 since it's first release. Sometimes different parts look similar on the dyno but on the track they're worlds apart in how th...

What carburetors did you try?

You might be uncovering the jets on the launch.

Have you bolted another carburetor on to confirm that it's not something else?

X2 on the return line, it makes a big difference with pump gas.

Good tracks. They're racing and getting cars from all over the country.