What jet size should I use?

[70RTdroptop]

Hi, all - haven't posted in a while. I moved from a lower elevation about 800 ft. above sea level, to a much higher one 5000 ft. Engine is 440 SIXPACK automatic. What jet size should I be running in the center carb? By the way, the car runs real good, but from what I've read the jet size may be too big for the elevation that I'm at.
Thanks!
Bob

[cudabob496]

on a normal performance 4 barrel, going from 1000 to 5000 ft, it is recommended
to drop two sizes. But always check the plugs to make sure

[jhaag]

unless you are certain you were correct on jet size before, don't be in hurry to change. most set ups are too rich. you say it is running fine, I say run it for awhile and check your plugs. then adjust accordingly.

[72ls5fla]

hey

i'm pretty sure the center carb has 64 jets from the factory.

Under normal elevations with the use of ethanol, they are to lean.   I had to step mine to 66 to help with ethanol lean-out.

If you are not fouling the plugs out or getting god awful fuel mileage - I leave it alone.
It is hard enough to get a six-pack to run well - 

[70RTdroptop]

Thanks for all the responses, everyone! I think I'll just run as is for a while and check my plugs to see if I need to change anything.
Bob

[Chryco Psycho]

That is the best formula