Which gears?

[u0061914]

I have started my I6 to v8 conversion this week. In the process found a fairly built 289 (cam and some headwork) with an AOD which was in another 67. I also picked up a 9" from a 69 Mach 1. The 9" alegedly has 3.00 gears in it. I also have a 9" 3rd member with 3.50 gears in my parts shed. With my setup, which are the preferable gears? I'm tinking that the 3.50s might be better with the overdrive. Any thoughts?

 

[2+2GT]

Absolutely use the 3.50.

 

[golf4283]

^^^ What he said. With that overdrive gear you'd be dumb not to go with a higher rear end ration.

 

[mr408]

Yep , go the 3.50 , you still will only be doing about 2000rpm in overdrive with 3.50 at 60mph, depending on your wheel and tyre diameter.

 

[68stang351]

3.50.

You wont like it with 3.00's in it.

 

[armand67Fstback]

Another vote for the 3.50s here.

 

[rbohm]

one more vote for the 3.50's

 

[65ShelbyClone]

+1 for 3.50s.

 

[calpolymustang]

I had a 3.40, but it seemed to be running a little too low with my 25.2" tires and .67 overdrive gear.

Now I have 4.11s, and ZERO regret. At 65mph, I'm spinning 2300; at 75, 2600rpm.
The response of the car taking off from a stop is much better. Keep in mind 1st gear is only 2.46:1

 

[tx65coupe]

With overdrive definitely the 3.50 gears over the 3.00 gears.

 

[57fairlane]

3.50, but you could easily go with more gear.

 

[6Stang7]

3.50, but you could easily go with more gear.

He speaks the truth. I have 4.11's in the 67 and I run around 2k on the freeway. Get the 3.5's.

 

[RGS0907]

I had a 3.40, but it seemed to be running a little too low with my 25.2" tires and .67 overdrive gear.

Now I have 4.11s, and ZERO regret. At 65mph, I'm spinning 2300; at 75, 2600rpm.
The response of the car taking off from a stop is much better. Keep in mind 1st gear is only 2.46:1

4:11s have a way of making you smile

 

[u0061914]

Thanks all. I'm now thinking that I may skip both and regear to 3.73 or 4.11s. They way the money is flowing into this project, what's the cost of a ring/pinion, etc!

 

[blown65]

I'd go no lower than 4.11's. Even with 4.56 gears and the AOD your looking at 2500 rpm at 65-70mph anyways. Just depends on the rest of the combo, but I love the 4.56's/AOD combo in the Shelby.

3.0 or 3.50's, no thanks.