[jhv48]

I’ve run both of those vacuum secondary carbs on two of my engines and wasn’t pleased with either one of them. Vacuum secondary carbs are designed for cars that are much heavier than ours.
You are running lean. The plugs tell the tale.
You’ll be happy with either the Holley or QFT double pumper. Right out of the box they’ll be a bit rich, due to your altitude. Easy job to drop down a couple of jet sizes on both primary and secondary sides till the plugs look right.
Order either one and don’t look back. You’ll love the difference moving from vacuum to mechanical secondaries makes.