Need advice for diff for 65 Dart factory hi-po 273.
I don't get it. I'm running 8:25 with 3:21 gears. Pulled off my rpm air-gap and put performer intake on earlier this summer with AVS-2 650 edelbrock. Mild 318 250hp 904 tranny. 25" tires in back. Anyway, was getting between 12-13mpg maybe 13.5 on hwy. After switching intakes maybe picked up 1/2 mpg. We do alot of cruising and would love to improve mpg somehow. I keep thinking since changing intakes I could get by with a 500 eddy. Anyway, saw your post and thought "how does he do that?"
There are so many ways to lose fuel economy , it ain't funny.
Economy starts with a lightweight car, a small highly efficient engine, very low cruise rpm, and ends with major tuning session.
But if I had a 318, it would be knocking on 24mpgUSg, Cuz it wouldn't be stock.
It would have alloy heads, a solid-lifter fast rate of lift cam, and a Dcr pushing 9/1 The cylinder pressure would be pushing 190. It would have a 4bbl with triple booster primaries, headers, and a free-flowing exhaust with dual full-length large diameter primary pipes, and huge triplepass muffs.It would have a close-ratio 5-speed manual trans and cruise at say 65=1800 rpm. I would stick it in a lightweight chassis of no more than 3400 car and driver.... cuz I already have one lol.
I bet I can tune that hi-compression teener to do better than 24.I mean I have a 367, that in one iteration easily surpassed 24, so a 318 should be a breeze.
But yer not likely ever gonna get that out of a stock low-compression LA-smoggerteen with an A904, and I don't care what gears it runs, or how light a factory chassis you stuff it into. Well, maybe
you can; but I sure couldn't,lol.
The point is this. if your 318 is only getting 13.5mpgs, IMO, there is either something you're not telling us, or your combo is in serious trouble.,