I'm rebuilding my f150 and am planning on a 4inch lift, and going to 33's. It has a 4.10 in it, do I need to go to 4.56? What I have researched says I need to go to 4.56. The tricky part is, I'm also putting in a zf 5 speed in with the wide gear ratio. 5.76-.76 What am I looking at then?

Thanks in advance.

 

What engine will power this rig?

I'm tempted to say 4.10's are enough with the ZF, it doesn't have a very deep overdrive compared to some of the automatics so you'll want to be conservative to keep highway rpms under control. BUT.... if this is a 5.0 truck then it'll need all the help it can get and a little more rpm is your friend.

 

It's got a 351 in it. What do you mean by 'not a very deep overdrive'?

 

What he's saying is that given all things the same (tires, diff ratio, transfercase) you'll be turning more engine RPMs at the same highway speed with the ZF as opposed to say an auto overdrive..


For example top gear ratio in the ZF 5 speed is some thing like .76/1 while an E4OD is .71/1 ratio... IMO the difference is so minimal its not even a factor, especially when you consider the ZF manual has 5 incremental ratio's...way better...

If I were you I'd just run it like it is with the 4.10s with 33s..That actually sounds about perfect to my ears... If you don't like it-----then spend the money and change the gearing...BTW, You want to highway tow in 4th gear (1/1) anyway right.. Should be right in the sweet spot..

 

with that 351 and 4:10s you wont even notice those 33s. Thats the exact setup in my F250
VVVVVVVV

 

Puts my mind to rest then, thanks. Couple months and I'll have a teardown/bloody knuckles/build thread for everyone.

 

Just out of curiosity, what about 35's?

 

You will def. feel the 35s, but the 351 will still have enough power to turn them at highway speeds easily. I had 37s on mine and was still able to use overdrive on the highways.

 

I've got 32's on mine, with the 351, and my that's with 3.08 gears. I wouldn't go to 4.56's unless you plan on some large loads. I'm not planning on going beyond a 3.73 setup if I go up to 33" tires, the 351 will push through that without a problem.

 

Some day, a couple years out, I'll begin work on our house and need it to haul stone, but I'll figure that out when the time comes.

 

Trust me, you are not going to haul much stone with that half-ton no matter what gears you have in it. You can put bigger springs on it, then the brakes become an issue.

I purchased an old 1 ton dump truck when I built my house. It still wasn't big enough to cost effectively haul much stone or dirt or whatever. With the price of fuel, I found it cheaper to have a local hauler bring any materials I need.