jmos4

Hi all,

I have a 65 Cutlass, 330 4v with a slight cam and currently a 3.08 rear end.(8.2 BOP)

The ​​​car is fine cruising, but from a dead stop is something to desire, so I am considering swapping in a 85 200r4 from a Monte SS.

What gear ratio as a 3.08 with the od is a 2.00 final drive ratio. I was thinking about a 3.90, but would there be a advantage or issue running 4.56 gears as that with the od would be almost what I have now. I currently can go 80-90 with no issues on the freeway.

Any suggestions or anyone else running this combo?

Regards,

GEARMAN69

your going from a 1.76 first gear to a 2.74 so that alone fixes it but I would go with a 3.23 3.42 3.55 3.73 which ever falls easier

matt69olds

joe_padavano

^^^THIS.


Do the math. Simply changing the trans means that in first gear, the 200-4R and 3.08 gears is equivalent to 4.80 gears with your current Junkaway. Too steep a gear means that you'll be hitting the rev limit at a much lower speed than you want. At the end of the day, you really need to match engine torque curve with effective final drive ratio (which accounts for tire diameter and trans gear ratio in addition to rear axle ratio).

jmos4

Hi again,

Yes I have looked at the final drive ratio, hence me inquiring about 4.56 as final ratio works out to be 3.06 which I am good with on the highway.
It would be nice to be able to lite up the tires on command as no chance of that currently.

I was ​​​​​​thinking 3.90 as that works out to a 2.61 final drive ratio, as the mid 80's 442's , Buick GN's and Monte SS's had 3.73 so a little more gear I wouldn'tthink be a bad thing.

Has anyone ran a higher, and how was it for driveability?

Regards,

Fun71

I have a friend who runs 4.56 gears with a TH700-R4 trans and he really likes it. It rips through first in a hurry and that is one of the things he likes.