Six Pack Roadrunner Clone

[69 GTX]

Subtract 1 jet size for every 2000 feet gain in altitude I believe is what I read.

 

[biomedtechguy]

Thanks. I am asking because it is a good possibility that my RB stroker will be built and dyno tuned in Michigan, and that has to be factored into the build because one of the main reasons I am considering that particular builder is their proven track record of extracting performance from the 6 bbl intake and carbs.

 

[Garys1969RR]

As you go up in altitude, you need to lean out the mixture to match the rarefied, or thinner, air. I think the ratio is 1 jet size smaller per 2000 feet rise in elevation. But I'm not sure on that. Maybe someone knows for sure. When I put this new 6 pack set up on the motor, I installed it just as it came from Holley. No jet change. It has been working great! Carburetors are self correcting to a small extent. Since there is less air pressure up here, there is less air pressure pushing the fuel thru the jets.