Falling on its face when you stab it definately sounds like the secondaries are coming on too quick. On the passenger side of the carb back with the secondary is a small screw. Under that screw is a small allen screw that is a set screw. The screw and the spring associated with it control how fast the secondary air dam opens up and how quick the secondary metering rods pull open. Mark where the slot of the screw is at and take your screwdeiver and allen wrench back there and start tweaking this. You will want to tighten this up a small amount, but you do not want to have it so tight that it won't open up. Now comes the fun, finding out if it works properly! When you have it set right, the tires will boil!
