Hey there Novaboy,
It is very cool to see a young person into muscle cars even though you are running a six. Trying to hang with your peers running all them cool rice rockets is kinda tough with you and your Nova. You gotta up them in uniqueness and coolness. Anyone can have a V-8.
I had a 62 Nova with a 250 Offy manifold and Holley 390 CFM. You said that the plugs are white colored, this means that you are not running rich. With a Holley there are so many adjustments to look at. I also had a "bog" on my Nova but I had a Power Glide 2 speed tranny. What helped me was to go to bigger accelerator pump nozzle and I installed a new pump cam. When you open the thorttle plate quickly, your vacuum goes away and it takes a 1/2 to 1 1/2 secs for the engine to start pulling air passed the venturies and drawing fuel. More gas. In your case with the TH350 you may also or first try to delay the opening of the secondaries. If they are opening to soon, this will also cause a "bog". I you can get yourself a Holley carb performance book if you want to learn about Hollies.
I still drive a inline 6 with a Holly 390. It is in a heavy 56 Chevy pickup. If I peg it at low rpms it will also "bog". So I just don't put my foot on it until I have some rpms built up thanks to the clutch. And I put my foot in it all the time.
Have fun.
Luis
