To fine my sweet spot, I temp installed a vacuum guage and zip tied it around my steering column. I changed gear/gas to get the most speed with the most vacuum.
Which oddly enough, is in 4th. In 5th(od) The load (even at the same speed as in 4th) Is so great that the vacuum goes to pretty much zero which results in the carb just spilling fuel into the engine. So right now, I dont really use overdrive until I change my rear end gears to something lower than 2.79s .. Keep in mind, with my combo, in overdrive, 80 mph is at 1800 rpms. I am going to aim to get 80 mph up around 2200 rpm eventually.
In overdrive, 80 mph, 1800rpms results in about 12-14 mpg.
In 4th, 80 mph at about 2800-3000 rpms results in about 18 mpg.
The smaller the bore, the faster the burn. You can run higher RPMs with good efficiency and (added bonus) they will handle more compression without detonating. My advice above was for the 4.00" bore of the motor in question.
The smaller the bore, the faster the burn. You can run higher RPMs with good efficiency and (added bonus) they will handle more compression without detonating. My advice above was for the 4.00" bore of the motor in question.
I think your post was clear. I disagree with your statement though. I think that there are too many variables to say that XX RPM is the way to go for X size bore to optimize fuel economy. Brake specific fuel consumption is not that simple.
Well, good, no misunderstanding. I was referencing the work done by others in other publications, not my own opinion or research. I should have made that clear. I don't have a dog in this fight (so to speak), just trying to provide some guidance to the original poster.