As Craig said, I had the best luck using a 58 jet...at your altitude it should be good. Currently I am using a Carter YF3211S carburetor (the one designed for your model 235) and an HEI that is a clone of a GM coil-in-cap model and it is doing fine. If for any reason you are using Pertronix products, please see the post I made in the Electrical Bay...might be information worth knowing. Good luck.
