318 carb issues

Sounds more like a jetting issue to me. Is the intake a single plane or dual? If single plane it needs a lot more of a pump shot or bigger squirters. Check the jets also.
If it wants to idle high look for a vacuum leak. I’ve been in the same boat when converting mine from TBI to carb

59E25BAD-4A61-4B34-B6E1-8542E4AC4373.jpeg