Tuning for altitude

[Ralph A Powell]

When I was working at the Ford Text track in Dearborn we would go on test trips to Denver where Ford had a small facility at Colorado Springs th do high altitude testing on fuel systems and brakes. At that time Ford had High Altitude kits for carb usage over 5000 ft sign included inmost jets,power valves and dist springs. They were in the parts catalog at Ford dealers.

[Tom Meyer]

I think Daves car is a 66 Chevelle 283/220 stocker. The carb on this combo is 485 cfm 4gc maybe with a cast iron 459 intake? Not alot of air flow. Back in the day my SS 283 with the same carb responded to leaning it out with jetting. The 2 plane intake with small lift cam will not have as good as fuel signal in the boosters as my SS motor. Also if he is running a glide with the one gear change, it may respond to higher rpm on the shift. But it is what it is. Good luck. Tom

[The Hawk]

Leave the timing alone, jet up 3 or 4 steps.

[Dave Muller]

Originally Posted by Tom Meyer

I think Daves car is a 66 Chevelle 283/220 stocker. The carb on this combo is 485 cfm 4gc maybe with a cast iron 459 intake? Not alot of air flow. Back in the day my SS 283 with the same carb responded to leaning it out with jetting. The 2 plane intake with small lift cam will not have as good as fuel signal in the boosters as my SS motor. Also if he is running a glide with the one gear change, it may respond to higher rpm on the shift. But it is what it is. Good luck. Tom

That's what it is, except I'm running a metric 200, so there's three gears. I'll give it a little less jetting and a little more timing in Q1 and maybe adjust some more from there. Probably bump the timing up even more for Q2.