1983 oldsmobile cutlass supreme wont start

I had some issues when I changed my olds 307 to a slightly modified olds 350 rocket, it would start fine cold, but hard cranking or slow, painful cranking when hot. Alot of it was the carbureator was allowing too much or too little fuel into the engine. I rebuilt the carb twice. The first time I didn't have a full understanding of float level drop and measuring as far as bending the brass tangs. The second rebuild I finally was able to remove a large part of the hot starting issue, along with retarding the timing as well. But it still isn't gone.