Gearing difference between transmissions

[Midnyteryder196]

Okay I had the black tranny with reverse and 72t spur, converted to the grey fo with 58t.. Is the final gear ratio the same between the 2? I understand I need to go down on my clutch 2 get roughly same gearing there, but just wondering about my overall gearing.
Thanks!

 

[chickenman242]

with a 3.3 trans in a 2.5 truck you need a 54t spur and a 22t bell that's the same setup on the 4909 trucks, if you a bit more punch go for a 20t bell. since you have a 58t spur I would use a 18t bell which would be the same roughly.

 

[Midnyteryder196]

with a 3.3 trans in a 2.5 truck you need a 54t spur and a 22t bell that's the same setup on the 4909 trucks, if you a bit more punch go for a 20t bell. since you have a 58t spur I would use a 18t bell which would be the same roughly.

I have a 2.5 motor in a 3.3 chassis, with 3.3 fo grey trans. The motor has a 20t cb on it, and the old black trans had 72t spur for a gear ratio of 3.6, the new trans has a 58t spur and with my 20t cb it's a ratio of 2.9.
I was going to go with a 16t cb as that puts me Back round the 3.6 ratio..
Is the final gear ratio between the 2 trans the same? Why did the grey one come stock with 58t? Is it because it's fo, and black trans had reverse?
I'm just looking to get to final drive ratio of what I had before. Right now it seems a lil sluggish.

 

[hotrodrob]

The gearing inside those two Trans are different that's why the spur is much smaller,..if I remember a 56-18 on the grey and a 72-18 on the black are the same ratio,...or close by 2 teeth either way

 

[Midnyteryder196]

The gearing inside those two Trans are different that's why the spur is much smaller,..if I remember a 56-18 on the grey and a 72-18 on the black are the same ratio,...or close by 2 teeth either way

So as long as I get the ratio between cb n spur about the same then the final ratio will be about what I had?

 

[chickenman242]

58/20 on the 4908/4907 truck 54/22 on the 4909 with a 3.3 and 72/18 on 4910 .
basically if you want it to be punchy on the I would run a 58 with either an 18 or 20t bell any lower than that and you will have no top end