So at MIR a couple weeks ago I had the duster out. Friday night is was running 11' teens at 122.8-.9mph on new tires. Last pass of the night it developed a surge at the top end that was even noticeable on the a/f meter (going lean). Saturday morning I decided to see where the fuel pressure was at since I hadn't checked it in quite a while. It was at the 6psi I set it at, and I decided to bump it up a little and went to 7psi. The first pass revealed it wasn't the pressure and there was crap in the needle and seat. Took it out after cleaning the carb and it went 125.5mph, followed by a few high 124's. Car was noticeably stronger in the top end and it was laying on the 7200 chip for awhile. A/F friday night was 12.9-13.1, Saturday was 12.4-12.8. On the dyno it made more power leaner. One psi, .6a/f richer and it picked up almost 3mph? Previous best mph, which was in better air it went 123.8. Ideas?

Maybe the crap in the needles and seat was a restriction Time to jet up to see if you can get it rich enough to slow the MPH down in the 1/4 mile If you can't do that you might want to try bigger neeldes and seats, I did that several times and went faster after getting it rich enough to make tha car slow down by being to rich Lots of gremlins out there, especially in the dang fuel systems Good luck, have fun

My limited experiance, the popular rule of thumb of 12.8 to 13.2 has never work out to the best et and mph. Usually 12.3 to 12.6. Probably suggests that my junk is not to efficient.

My conclusions is that you really need to figure out what is the best for your car, and let go of the rule of thumb and dyno data once it is all together.

Rich/lean numbers are just that, numbers. The dyno cell is not the track. Jet for speed. Under hood air flow , fuel slosh, vehicle load, actual rate of acceleration all can not be duplicated on the dyno. Looks like your're on the right track. My 2 cents.
Doug