A while back I had a '68 427 tri power Vette. It came with 8, yes 8, spare carbs for the tri power set-up.

After much pain and time playing with what I had I wound up buying new carbs and still did not like it. I never could get it properly leaned out. I switched to an 850 holley vacuum secondary carb and the car sprang to life like it had never before!

For what it's worth .................

Good Luck, Kitz