I have a 67 Cutlass 71,000 miles with a 330 that I believe to be stock and a Holley 750Cfm carburetor and will be attempting to tune it this weekend. It feels a little sluggish off the line but at higher speeds and rpms it feels ok, responsive and plenty of go. So first could the problem be that the carb is to big for motor? I have a 600Cfm would my time be better spent swapping them out? I also have a question about my secondaries I can never hear or feel them open up. I had read that on a properly tuned carb with vacuum secondaries you shouldn't hear or feel them but I have owned a decent amount of 4 barrel cars and I always heard and felt them. When I was a Kid I would flip the top air cleaner lid so it was louder always loved that sound.

 

I would say the 750 is big for the 330. It could feel sluggish because of your rear gear. Do you know what it is?

 

I don't know for sure but it is the Holiday coupe and I read they came 3.08

 

There is a 2 letter code stamped on the passenger side axle tube that can tell you whats in there. The last 2 4dr 67's I parted were 278 gears. One was a 12 bolt cover and the other a 10 bolt.

 

I will take a look in the morning I appreciate the info.

 

If you still have the ST300 the torque convertor may not be operating correctly with the linkage change to the Holley. It has a variable vane torque convertor and when not operating correctly it's a real dog. Also you need to check your distributor advance and make sure your dwell and timing is correctly setup. If you have 2.56 gears then it's going to be even harder to get low end torque out it.

Yes, the 750 is probably a bit too big, chech and see how the plugs look to be sure. Your reading is correct, you should not feel the secondary's open up, but you should feel the passing gear kick in. Holleys are not loud like a Quadrajet.