Recently rebuilt my Dual Holley 550s. Put in brass floats new gaskets with the rebuild kit.
Rebuilt in or about May. Ran fine.
Recently, engine runs fine for about 20 minutes and then after it gets thoroughly warm it runs rough at less than 1/5 throttle. Smooth's out when I give it more gas. Idle also drops. If I let sit for a while it is harder to start than normal and have to depress accelerator several times or pump gas with fuel pumps but will start right away once running and shut off and re-start quickly.
Floats seems to be working. Checked through the site hole. I leaned it out a bit and it runs a little better. I was going to lean it out more but thought you guys might have some suggestions.
I use Marvel Mystery
oil with my gas. Maybe I'll stop that next fill up and see.
Thoughts