Can anybody HELP? I have a 72 GS350 that just won't run right. This car nas seemed to always run rich no matter what I do. It has an Edelbrock 600cfm, Poston S-Divider intake, 9:5-1 pistons, & Ignitor conversion kit in it, but here's the kicker, I'm at 7000' altitude! Any help? PLEASE!
We need a little more information to help you out. You say you are at 7000 ft. Where do you live? A lot of people are going to tell you that your carb is to small but at that altitude a smaller carb may be better for getting your 3800 pound car moving. Has the cam been replaced from the origional? Do you have a vacume gauge? If so hook it up to a manifold vacume source and tell us how much vacume you have in gear with the break on and the tires blocked. Also tell us how much vacume you have in park. With the engine off slowely turn the idle mixture screws in and count the number of turns they are out, then return them to their starting positions. Write this information down as you will likely forget it as soon as you move on to some thing else. Tell us what kind of stall you have as well as your final gear ratio. Also tell us how much timing you are running and if your using vacume advance or not. What kind of Pertronix module are you using? Does it have magnetic ring just under the rotor? As soon as you provide this information we may be able to help you.
How can a smaller CFM carb be better for high altitude?o No: I would think that since the air is thinner up there (less O2), you would need MORE CFM to get what you would normally need in a sea level motor.
Wow 7000 feet!:eek2: That's up there. If you just slapped that Edelbrock carb on without tuning it, I'm not surprised it is running rich. The problem is that at higher altitudes you have less atmospheric pressure and the air is less dense. So the engine cannot inhale the way it does at sea level. Most Edelbrock and Carter carbs are jetted on the rich side right out of the box. You need to change the jets and rods for a leaner calibration. On the Carter/Edelbrock carbs this is pretty easy. You can change the primary rods without even taking the top of the carb off. If I was you I would get a copy of "Carter Carburetors" by Dave Emanuel, SA Design Books, ISBN 0-931472-11-3. It explains how to tune these carbs. If you have a cam, you may also need to modify the power enrichment system. Engine vacuum holds the rods down in the jets against spring tension. If you don't have enough vacuum at idle, the springs may be letting the rods rise out of the jets. Changing springs is very easy, like the rods. Edelbrock makes a strip tuning kit. You need to do some reading, get the kit, and start experimenting. Good luck. BTW, post your name
