Holley Idle Circuit Mods

[1969_Mach1]

M1FF,

Holley's are very simple carbs to work on. If you can adjust an SU carb you can work on a Holley. The Holley on your daughters Mach 1 is probably ready for a rebuild. If so, use either a Holley, AED or QFT rebuild kit. They come with better gaskets than kits from auto parts stores. This is a good reference book to have for Holley carbs. http://www.summitracing.com/parts/sad-sa216/overview/

I always suggest that book. It covers a lot for Holley carbs including the commonly overlooked critical throttle plate position when setting idle speeds on Holley's. You cannot simple turn the screw to set the idle speed. There is a small range of position the primary throttle plates need to be in at idle.

Best Regards,
Mike

[Mach1FatherFigure]

Thanks for the words of encouragement, I need them!
The carbi is brand new and suposed to be factory corect for the 351. I find it hard to believe! I shall get that book and learn. It would not be the first time that 'factory' and 'correct' were not the same thing.
Vizzard has done some amazing stuff in his time.

[1969_Mach1]

Is that one of those spread bore type carbs?

I think for your daughters 351C I would have been inclined to install one of Holley's 750 CFM vacuum secondary universal carbs. Maybe an intake manifold swap as well if the stock one is a spread bore type. Although there are fairly decent spread bore to square bore adapters these days.

For some reason the best performing 750 vacuum secondary Holley carb were the first two generations, List 3310, with no extension to the list number and 3310-1. It was actually a 780 CFM with its down leg boosters instead of straight leg. But, even though slightly larger it works better than any of the later 750 cfm vac secondary Holley's. Even on smaller motors. Ford used it on the Boss 302's and GM used it on Z28's with the 302 motors.

Regards,
Mike

[Mach1FatherFigure]

I will check and report on carbi model. I believe it is a Vac Secondary unit, similar to the Rotchester Quad I had on my Statesman.
I am the first to admit I need to learn more....