This can't be right.

Just for shits and giggles I did thee old figure out your MPG thing and I am getting 16.5 MPG on a F_ing 250 1bbl. What am I supposed to be getting? Also my car hits whats sounds and feel like around 4k rmp @ 70 mph WTF? Is it the rear end gears or the 3spd that's killing my topspeed. I feel like old Granny Saggy Ass on the freeway cause I can't keep up with anybody. I never payed it much mind before due to the fact that I was living in a small town for a while, but now that I am back in the city it's really showing. As it is am any buying a 4 banger as a 2nd car to I don't feel so violated at the pump.

You didn't say what year your Nova is but I had a 68 with the 230 / PG auto that ran very nice and my MPG averaged about 18. These cars don't have overdrive that's why it is revving high on the highway. It shouldn't be 4000 rpm though. Maybe 3000 at 70 MPH. Still, if it's running properly you shouldn't have a problem keeping up with traffic. I could easily cruise 80 plus all day when I wanted to.

I think I need to get my diff looked at then. My car is a 72'. I think somebody put some different gears in the back before. 80 is murder on my car.

Check to see what the ratio is first. Jack up the rear end, put it in neutral.

Make a chalk mark on the drive shaft and one on the inside of the tire. See how many turns of the drive shaft it takes to get the tire to go around one time. The number of turns will be your ratio. I'd guess that you probably have a 3.73 ratio. If it takes roughly 3 3/4 turns, it will be 3.73 : 1.

If the rear is also a posi, it might be worth some bucks. Even more if its a 12 bolt. A stock ratio 3.08 rear should be available somewhere and would cure your gas mileage problem.

Bob

Check to see what the ratio is first. Jack up the rear end, put it in neutral.

Make a chalk mark on the drive shaft and one on the inside of the tire. See how many turns of the drive shaft it takes to get the tire to go around one time. The number of turns will be your ratio. I'd guess that you probably have a 3.73 ratio. If it takes roughly 3 3/4 turns, it will be 3.73 : 1.

If the rear is also a posi, it might be worth some bucks. Even more if its a 12 bolt. A stock ratio 3.08 rear should be available somewhere and would cure your gas mileage problem.

Bob


Kick ass bob, thanks. I didn't know it was that easy to do that, I was about ready to get have some shop do it. The more you know...

You're welcome, I've only been crawing under cars for the past 35 years. I like to work on the older cars, the newer ones have too much BS on them and are getting harder to fix. Glad to help someone out who believes that older cars are better.

Bob

You're welcome, I've only been crawing under cars for the past 35 years. I like to work on the older cars, the newer ones have too much BS on them and are getting harder to fix. Glad to help someone out who believes that older cars are better.

Bob

Oh man I grew up listening to stories from my dad about playing "fetch the 20' off the dash" with his 454 El-Camino and how he drove a torque-happy 64' off a wet bridge into a creek bed without a scratch on his head. So old cars are in my blood. Somebody's gotta keep the history alive.