3.55 gears

[6t7mstg]

Hello guys, I'm new to the forum and was wondering what gears you guys are running in the rearend. I have a 67 coupe with an I6 200 and 3spd manual with 2.79's in there now. Thinking about 3.55's, will that give me much more punch?

[matcox83]

My 66 6 cyl was originally a 3 speed but I swapped in a C4. Original gear was 3.20 with open diff. If you still have the 7.5" axle, you don't really have any choices. More importantly if you go too low (high number) your rpm on the highway will be too high. My opinion is 3.20 would be the lowest ratio to go with unless you do a T5 swap. Hope that makes sense and helps.

---------- Post added at 06:56 PM ---------- Previous post was at 06:52 PM ----------

It would give better acceleration but highway RPM would go too high. If you still have 7.5" rear end though you can't find a gear. Gotta swap to 8" to change gear.

[6t7mstg]

Thanks, that is exactly the kind of info I was looking for. I did swap out the 7.5 rearend for an 8, thats why I have the 2.79. I will go with the 3.20's, thanks for your help.

[Sainte]

I had an I6 with the 7.5" 2.80 rear. At 60 mph it sounded like it was going to explode!

I am dropping a 289 in it currently along with an 8" 3.55 rear. A LOT more work than I anticipated swapping a V8 into the I6 body!

Oh, almost forgot, I junked the three speed transmission and I am dropping a T5 in it from a 94 Cobra. I had to replace the input shaft and bearing housing in order to use the 93 5.0 bell housing so I didnt have to use the adapter plate.

[6t7mstg]

With my I6 and 2.79 rearend, it feels like I'm starting out in 2nd instead of 1st. I also have larger than stock tires too, so I think that makes a difference on the gearing.