so i went back to my log, which i still have since the buyer of the car didn't care if he had it, and looked again at the info that was there before changing the rear end from 346 (stock for a 300 na) to a 307. my kids were driving the car and there is evidence of at least eight tanks but they were a little sloppy and didnt always record all the info so there were only three tanks that i could decifer. they worked out to 21, 26 and 22 mpg. i can tell that the one at 26 included a trip to colombus oh. so that was pretty much all highway.

so then we changed the rear to 307. i wont put a sharp pencil to it but that is about a 10% change in ratio.

the next twelve tanks i did. the mileage on them was 29.4, 20,26,28,28,25,30,20+,28,20-,22 and 20. the ones near between 28 and 30 were all highway. the others were mostly town driving.

so it is not a double blind test using computers and regisered engineers, but it is sufficient for me anyway, and i think i am more critical than most, to say that the mileage increase was pretty close to the same percentage as the gear change.

in any case it is enough to convince me that if i wanted a mileage increase i would spend good money doing it and expect this kind of results.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.