[Tom Vaught]

A bit more on 6-Pack carbs and 3 BBL Carbs.

The first Holley "Tri-Power" systems for the Big Block Chevy Engines was offered in 1967. I have a Hot Rod Magazine Cover picture somewhere (1967 time frame) with a prototype set of carbs mounted on the BB Chevy Engine. This was taken before the final casting design was put into production for the Corvette Engines.

In 1969, Holley offered the 6-Pack carb set-up on the MOPAR vehicles. Basically the same set up as the Corvette.

So now we come to the first technical point for the day. I have attached a picture showing the two metering plates offered on the secondary carbs. The Rectangular Plate being the early plate (from 1967 to 1969) and the "second design" plate (with the angled lower edge plate, see picture). They are not interchangeable. So if you have early carbs some of the Hot Rod (aftermarket) plates with removable jet capability may not work and you will be wondering why. See aftermarket plate pic.
It has the shape of the 67 style plate but is really designed for the 4 BBL vacuum Secondary carbs. More on 6-pack and Corvette 2 BBL carbs later today.