Tim (NAPA68) and Tracey's beautiful 1966 Corvette 427-425hp

[dykstra]

Gorgeous Corvette Tim!! Congratulations on another bad azz ride!

[napa68]

Like any new car, they can be fickle til you figure them out or you straighten it out. So, after trying to tune on it........and being able to run the idle mixture screws all the way in......off to Eric we go!

And this is what he finds and explains in his Facebook post......

Vintage Musclecar Parts
Omcto9gbol8ear2 o9ie23 3at 5:42 PM ·
Holley 3247 For a '66 427/425 L72 Corvette for Tim Schuetz of Boulder Motorcar Company.
This one came in for a basic rebuild and to diagnose a few leaks and a fat idle condition. It had been previously rebuilt by another vendor and had several incorrect small peripheral components that had to be replaced.
I also noted that the metering surfaces on the main body were warped to Hell and back, especially the primary side. I figured that was likely the cause of the fat idle, but there was another gremlin lurking in the shadows that had to be sent packing.
The carb failed the first live test miserably. It was Pig fat rich and the mixture screws had little affect. I popped the front bowl and block off and checked the primary block for warp. It was out over. 020" in several places, and that's a bit too far out to get flat again.
I cheffed up another original primary block for it (this one checked out with only .007" warp) and buttoned it back up, and it ran like a Swiss watch on the follow-up live test with perfect mixture screw response. The only hang was a tiny hesitation off idle which happens intermittently on these '66 780 carbs that use an .021" primary discharge nozzle (squirter). A swap to a .025" nozzle cleans that right up.
This is why we live test whenever practical and possible.


The car has never run this good and suspect it has not in a looooong time. Thankfully we still have guys like Eric around for these old stoves!