I took the Vette for a ride tonight. It's freezing (approx.30F). The 1st time for a car who spent the last 34 years between Florida and New-Orleans. I drove a few miles, the time for the beast to come alive. Once hot enough, I start flooring it a little.

First in 4th gear: At 4000 rpm, the power shut off ???????? ... Try again... the same ????? Try in 3rd gear... no problem... the engine rev's up to 5000, 5500...

A few miles later, I decide to floor it again, for real this time, in 2nd gear: Power shut off at 4500 rpm, I keep flooring it just to see... power comes back at 4000 rpm and take me back up to 4500 rpm... shut off again... slows down to 4000 rpm ... and back up to 4500 and so on. Whats' up ??????????

Christian38681.7203819444

Sounds like a fuel problem. Could also have a problem with the ign. system.
Does your car have the Transmission Control Spark solenoid? If so, it is designed to give full vac. to the dist. in 4th gear. I don't think that would actually kill the power, but it could effect it somewhat. Might check the fuel system(filter-pump output), and also, check the points to see if they are burned, or out of adjustment.Adams' Apple38681.7942476852

If you have points in the distrubitor, the spring on the points may be weak causing the points to "float" at higher rpm.   You could connect a dwell meter to the ignition and watch the meter.  If both change at the same time, replace the points.

Never had this problem on a vette, but on a truck I have had a similar problem happen and everytime it turned out to be the spark plug wires.  The inner cores overtime will eventually just burn up and then they have to much resistance to fire the plugs what happens is a power loss at a given rpm almost like having a rev limiter.  Let off the gas and let the engine come down to a lower RPM and it would run just fine.

Sounds to me like your choke is sucking shut on high flow. I've been there. It just slams off without breaking up first.. Right??

Easy fix if that's it. Loosen the 3 screws on the electric choke housing and twist it tighter open. If that makes it go away, fool with the adjustment till you get on the edge of easy cold startup, then crakn 'er down. It's just not used to being cold. Can't blame it!!!!

Dave

At least I have several avenues to look at.

 I noticed the exhaust was firing when downshifting. (Very nice light in the mirror at night!).

Does this help narrowing the field to search ?

fire in exhaust means unburned fuel in the pipes, might mean over rich condition in carb, also check te coil.

Also when the choke closes it loads the system up with raw gas, flooding it temporarily...

Dave