Stop in for a cup of coffee

(Me) There is a good chance I would, but maybe I wouldn't. May be best not knowing. I read through so many people spending so much time and money over 12.5 vs 12.8 (made up numbers just for example) that they just go crazy. This is a toy, I get 12mpg (best was 15mpg over a 6hr drive) with 2 antique race carbs on a big block. Could I fine tune the combo, yes, and that is what I am trying to do. The car's reaction, drivability and spark plugs should tell the story. I am less concerned over a magic theoretical number. Every engine is going to be different, despite the same basic constants. SBC vs SBF vs BBM vs Hemi vs.....All each will have their own happy place. Then figure in gearing, weight, etc. I see it as the whole package effecting the running and the tune. I could hit a magic number, and maybe it will get the best overall fuel economy or help me pick up 0.010 in the quarter. I just want it to continue to run good and tune out the 10-20% that it is lacking.


In the end, I just want 2700-3000 part throttle to not stumble and the idle or part throttle to WOT fixed. I am very happy with all else. @Mattax has been tons of help. Being winter it is very difficult as there is no testing to be done.
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I’d say this. An AF ratio gauge should be used as a reference tool to tune. It’s not the be all and end all and in the end, it’s only as accurate as it’s tolerances.

The best thing would be tune it until she runs good, schedule a chassis dyno tune where they’ll measure and tune it all out. Freiburger just had his BBC chevy tuned on the dyno and made a video about it. Averaged 18 mpg and made the most hp it had ever done, all while at 10.x A/F ratio.