Well, I finally did it. I decided to go with an Edelbrock 1405 on my '69 K20. I drove it up and down the road a few times tonight just to see how it would run. My question is which vacuum port do I hook my vacuum advance to? Right now I have it hooked up to the one that advances the timing at an idle with it hooked up. If I hook it up to the other port, the timing doesn't change until I rev the motor up. Which one is correct? It seems to run really well the way it is. It idles really smooth and drives good with no spark knock at high RPM. The initial timing is set a TDC, which is what the motor's manual I have says. My engine is a bone stock 350 (except for the new carb, that is). I am running regular unleaded with Lucas gas treatment every tank. Thanks in advance.