Engine Miss, Help!

[daren44]

360, 10:1, holley 4412, stock fuel pump. Car ran great at thursday night practice last week. Finally got handling going the right way, car was running good. Took the car home. Changed the oil. Filled with gas (114 octane) saturday on the way to the track. Unloaded the car and did a few practice laps. Car started to miss very slightly off the corners. In qualifying the car missed badly off the corner and end of the straightaway, buy cleared in between. Shot in the dark and checked carb for trash and replaced plugs. Car ran even worse in the race. It would miss off the corner once I gave it full throttle. Then it would clear, and miss again halfway down the straight or at the end, or both. Then one lap it would run fine. It was only missing at WOT. It wasn't a backfire type miss, kind of a blubber. Today I ran the car in front of my house after completely cleaning the carb. Ran beautifully until the temp got to 180, then the miss came back. A slight miss at 3000rpm when I gave it full gas, then another at 5800 rpm. Clear in between. I changed the coil, same thing. Only missed once the operating temp got above 180. Changed the distributor, same thing. Checked the fuel filter, ok. I haven't changed plug wires yet, or carb, but are there any suggestions or insight before I change everything? I am running 70 jets in the carb. I've raced this exact setup 5 races with no miss what so ever. The new plugs looked like new plugs after the race, no carbon or discoloration. I'm at a loss.

[Mod57]

Had a similiar problem last year, it was my ignition control box.
Worth a check

[cageman]

Had the same thing. Try cleaning the little brass colored vent holes in the carb. They cause a problem if they slightly get plugged. Then check the needle and seat for trash. I had a piece of rubber that was jammed in there too.

I am starting to run a wissota street class and I was wondering what jets to run with a 4412. And why are you using 114 octane when you dont need to.

[daren44]

Well, the miss is gone. So is the motor. Something went awry last night. I'm assuming the two were related, but I haven't looked further. Engine turns over really hard.

I run 114 because some people tell me 93 is enough. Others are scared to run anything other than racing gas. I guess I'm either cautious or stupid.

I was running 70 jets. Tried 68's last night. My friend is running 65's in a similar engine.

[cageman]

So what went wrong?

I am going to start with 73 for jets in my carb. I run 100 octane VP and I have 10 to 1 360 to. Gas is spendy