AJ/FormS
Thanks for the detailed explanation into the manual trans sbm tuning differences. I was unaware that you could get into the 30 mpg range but understand why you defined it as difficult. I definitely have zero experience tuning the sbm for manual, and auto was not exactly simple as it has its own challenges. But it sounds like the automatic might be a little more forgiving in some instances, but maybe not. Tuning my 340 was all my doing with guidance from my friend that tunes dual Carter AFB 750s on his Hemi/4 spd. He doesn’t play with sbm or automatics but the Eddy carb was where he knew what to do, and I learned all I could from him to be able to tune my 340. The timing curve was where I took a few guesses and got lucky that the car liked it the first go round. 20 to 34 sweep. Like I said I don’t use vacuum advance because I didn’t like that it took the timing past 34 as I believed that to be risky? Car will idle down to 700 rpm but I have the idle set to 1300 rpm for the automatic. I have reliable and fun at any speed I choose and it does get good enough mpg considering I was not targeting that. So given the circumstances I was thrilled to get up around 12 mpg considering my setup. It’s not easy to find good carb tuners with so many people installing EFI these days. Seems like even running points these days scares everyone. But I fried a Pertronix and was over that instantly… I choose to build an old car because I can fix it… so on went parts I could actually fix.