410 vs 356 in dana 60 rear

[bandit]

Anyone know the top line pickup from downgrading from 410's to 356 in the rear? I am doing about 3500 rpm at 55mph now. How high will the mph get at that same 3500 rpm if I go down to 356?

 

[RustyRatRod]

That would be a 3.54 gear and I would say it'll drop by about 1000 or so RPM.

 

[bandit]

Oops your right. I meant to say 354. What do you think it will push speed vise at 3500rpm? I only ask because that is where I prefer to not go over if highway driving. Just need to know if this will get the speed up enough.

 

[RustyRatRod]

I would guess about 65.

 

[terzmo]

Oops your right. I meant to say 354. What do you think it will push speed vise at 3500rpm? I only ask because that is where I prefer to not go over if highway driving. Just need to know if this will get the speed up enough.

need to know tire height

 

[RustyRatRod]

need to know tire height

Why?

 

[HT413]

Tire only matters if you change it. Rusty's right, by my math, 55mph x 4.10/3.54=64mph. But at 55 mph, it'll go from 3500 rpm down to about 3000 rpms. Maybe adding an inch to your tire diameter will help a little, but not much.

 

[bandit]

Thanks! That is what I needed. I already have the 354 gears. Just debating what it will be worth to swap them out.

 

[beezee]

Here,s a calculator to help you out.
http://vexer.com/automotive-tools/speed-rpm-calculator

 

[Cranky]

Tire only matters if you change it. Rusty's right, by my math, 55mph x 4.10/3.54=64mph. But at 55 mph, it'll go from 3500 rpm down to about 3000 rpms. Maybe adding an inch to your tire diameter will help a little, but not much.

That's about a 16% change....should math out the same on rpm. In my calculations, you should see about 2950 or so with the change. It's a worth while change. I stuck on a tire that's 10% taller than stock on my diesel. Didn't see much difference in mileage (they changed the fuel to low sulfur at the same time) but at least I reduced my rpm to put my engine into it's peak torque at the cruise speed I was looking for.

 

[terzmo]

Why?

two or more answers....tire height changes rpm at same speed....does He have 14's....15's or whatever...410's at 60 with 14's will not be the same as 15's at 60's.. at the same speed Lower RPMs at 60 with 15's or taller tire...(few 25.5 inch tires available with 15 inch wheels).same for His "356" gears...lol

 

[bandit]

Any opinions on a safe rpm to stay under for extended(highway) travel? Stock 383 on 70 Charger, 4 speed. I am assuming I want to stay under 3500 but is that too high for running long term?

 

[Cranky]

The more rpm you run, the faster the engine will wear but that said, 3500 isn't that bad but the question is, how often do you run on the freeways? Also, what is your main intent for this car?

 

[bandit]

Mainly a cruiser car for the weekends and such but it will see highway once in awhile. I go to Wisconsin for gas which is about 1hr 20 mins away. Been filling cans so far but want to start taking the car. About 40 minutes of that is Interstate.

Been thinking about taking her to the 1/4 mile up in WI too to see what it will do.

 

[HT413]

nothing wrong with 3500 so long as you can enjoy it. If you'd prefer 2950, go for the 3:54's. i run 4000 rpm's to go get ice cream w the kids. And they wouldnt have it any other way.