Looking to regear my 94...
Its a 300 w/ the m5r2 and 2.73 ratio..
She's a slug, and I can live with that, I'm just afraid that I'm lugging her, b/c currently the best mpg ive acheived is 11mpg (60/40 highway)
In OD i cruise at around 1300-1400rpm

Worth it? Yes? No? Why?
Thanks yall

 

A 2.73 ratio is definitely highway gears, going to something like a 3.55 is going to decrease your highway mileage because you'll be at higher rpm's driving the same speed as before. Your acceleration would be better, but it wouldn't help mileage. I've got a 2.47:1 rear end in my truck and mine has enough acceleration for me, I can spin my 33's if I'm in the mood, but its no racecar. I get about 14-15 mpg with mostly in town driving and thats lifted with 33's. Chances are, something else is wrong. A tune up and some basic maintenance would probably increase your numbers.

 

yeah, I was getting 9, before a thermostat change and a full tune up.. Probably going to do the o2 sensor next

 

I just changed my o2 sensor. It seems to help a little, but I haven't gone through a tank to know for sure. I didn't have a check engine code for it, but I figured a new one couldn't hurt. It was about 30 dollars and only took like 5 minutes to change.

 

Perhaps try running in the lower gears longer before shifting, and leave it in 4th on the highway to see if the fuel economy changes much.

If it improves, then suggest a re-gear would be worth considering - although suggest it will take thousands of miles to break even on the cost. If it doesn't improve - then suggest to look at other things such as engine tune and condition, dragging brake, excess baggage, etc.

 

I'll try w/o od for awhile and see what happens... may regear just for power....

 

If you want to regear it, I have my stock ring and pinion that came out of my truck. I swapped to 4.56. The rear is for an 8.8 axle, and the front is a Dana 44 hi pinion. The rear ratio is 3.55, and the front is 3.54 (or vise versa; I can't remember). You can have them for the cost of shipping if you want to try these.

 

^
shot you a pm

 

Holy crap man. Yeah, you ain't gettin' nuthin' for mileage with those gears especially if you're not highway driving a lot. I've been playing around with my gearing for $90 a pop at the junkyard. It's going to depend on your tire size but you should get closer to my mileage of 16-17 with 3.55s. Same engine and trans.

 

Just did a full tune up and changed the stat b/c the engine was never reaching op temps.. That gave me a 2 mpg increase
I do alot of stop and go highway driving(highways with stoplights)
Going to experiment also, however my junkyard is cheaper than yours, but i have to pull it myself