3.25 rear-end gears VS 3.5O rear-end gears performance question

[skull]

0K , the housing is leaking in the 193Oish mopar thingy, it is egg shaped where the pinion goes thru and cannot be rebuilt:

l have chance to get 3:5O's to replace the 3:25's in her now. don't know if their posi but chances are they ain't.

the question is how much of a performance difference will it make ..[S

the car weighs 24OO and right now gets 25mpg will go from O to 6O in about 4 seconds with the 3OOO stall, 375HP and 31 inch tall tires.

it's a blast right now, will the gear change affect it much?

somewhere there is formula, but l can't find it.

l did circle track stuff most of my life when the family raced and set up for the straight line is totally different and honestly l don't know much about it.

just wondering if it is worth the change or just find a 3:25 and stuff back in it.

the gas mileage will probably go down a bit, but l think it will respond quicker off the line and still be a blast to drive.

thanks in advance,

Later

 

[Tripper]

I switched from 4:11 to 3:73 in the Chevelle, made a big diff but mainly on the highway! RPM's went from 3500 to 2100 at 70mph, made cruisin' much more comfortable. Thinking about going from 3:50 to something closer to 3:00 in the Nova.

BoB

 

[Sam_Fear]

You'll gain about 7% RPM's at the same speed with the 3:50's. So if you're turning 2500RPM at 65MPH now, you'll be turning nearly 2700RPM with the gear change.

 

[endicott_jb]

You'll feel a little more torque from the 3.50s which will make your 0-60 time go down. The downfall is you'll lose fuel mileage as you're RPMs at cruising speed will increase.

 

[Bamamav]

I went from a 2.79 to a 3.00, about 250 more rpm at 60 mph. Didn't really see much fuel mileage difference. It did take off a bit better though. I may put my 3.55's in when I get the AOD in.

 

[skull]

Thanks

thank you guys[cl

so l am going to go ahead and change them if my friend comes thru with the 3:5O's he thinks he still has somewhere, talked to him last nightand he's looking for them. sounds like the rest of us, l got'em SOMEWHERE 'round here

well, a bit more ZOOM off the line will be fun, interested to see how much the change shaves off the O to 6O times.

right now at 6Omph the tach says around 24OOrpms so it will likely go to 26OO/27OO and l can live with that, probably from what you guys are stating l may lose 1/2 mpg.

Later

 

[Willowbilly3]

If someone changed them and didn't tell you, you might not even notice the difference. I went from a 3.70 to a 3.50 in the rpu and the only difference I could see that I couldn't get 4th gear scratch any more.