Donor mustang rear end ratio

[Fordman114]

I just ordered my second FF kit. I built a MKIV roadster in 2023. I ordered a 35' Hot
rod Truck and I am trying to gather parts. I have a 408 stroker going in it, I am looking for an E4OD transmission and a mustang 8.8 rear end. My question is what would be the best gear for the rear end. I have a 3:55 IN THE MKIV but most of the axles I have spotted are 3:31 or 2:73. Any suggestions ?

[Jeff Kleiner]

The E4OD has a 2.71 first and .71 fourth gear. These will play well with a 3.31 giving a snappy feel off the line and an overall final drive ratio of 2.35:1 for highway cruising. The 2.73 would be really lazy from a start and way overdriven in fourth with an overall final drive of 1.93:1.

Jeff

[Fordman114]

Thanks Jeff. I did some math with my wheel and tire choices and came up with the same opinion. Just found and purchased a 8.8 with 3:31 gears.

[DanQ]

I used a 3.00 gears in my '33 and love it. The car is so light, you really don't need deep gears to accelerate , plus the noise level is low due to it running only 1,500 rpm @ 55 mph. It is also a big reason I can get 23-24 mpg on a road trip which is nice with the small fuel capacity we have. (5.3 LS with a 4L65 automatic)

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