Bronco Forum - Full Size Ford Bronco Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
769 Posts
Discussion Starter #1
i been looking at re-gearing my bronco so my puny engine and tranny dont have to work so hard with the 35"s. I kinda wanna go with 4:88 so i have the power but idk what would be the best set up. The motor will have edelbrock performer intake and cam with a 4bbl carb, im looking for good low-mid power so probably 4:88's.
 

·
Cadillac of Men
Joined
·
3,787 Posts
i have a weak 351m, C6 tranny, and 4.56....and I hate it. On the highway, it screams. If you drive on the highway, I would get 4.10s. If you rarely drive on the highway, I would get 4.56's. If you NEVER EVER drive on the highway, go with the 4.88's. Your top speed would be like 32 mph.
 

·
Registered
Joined
·
7,167 Posts
PLEASE READ THIS!!
http://fullsizebronco.com/forum/showthread.php?t=355

There is a reason it is the FIRST sticcky in the tech write up.

"These are figures that I came up with, to do your own just do:
Circumference of tire divided by the gear ratio you want.
Then compare you answer to the stock forward measurement of 25.5"s and then you will know if it fall over or under".
 

·
Registered
Joined
·
7,167 Posts
I am going to run 4.88 with 37's
Once you do the math you will see why.
 

·
negative creep
Joined
·
8,651 Posts
35s and 4.10s. it has plenty of balls to, it will burn rubber with 35s locked. same RPMs as 31s with 3.55 (ok, so it's slightly higher, but its as close as you're going to get anyway)
 

·
Registered
Joined
·
7,167 Posts
Andy, it is because you had to many rum and Cokes.
 
B

·
Guest
Joined
·
0 Posts
Plan for the future! I got 410's with 33's and now I'm running 37's. I get away with it cause I got plenty of power and a granny gear (5.29). Overdrive will let you go with lower gearing too! Just some things to think about.
 

·
Registered
Joined
·
183 Posts
Beerman and I were just talking about this. Our rationale is that if you have the E4OD, you should be able to get 4.56 with 33's no problem because your final drive ratio will only put you about 192 rpm over the stock RPM at 70 mph. I sit at 1750-1800 at 70 with 32's, so if I got 4.56, I'd sit at 2000 RPM at 70, whihc is just about perfect considering the 33's.

If anybody has any insight into this, please, weigh in!
 

·
Screw the Jeep Thing
Joined
·
4,522 Posts
I'm running basiclly what you'll be running. 36" TSLs C6 and 4.56s I run at 65(I Think I dont' have a speedo cable) jus under 3000 RPMS
 

·
Registered
Joined
·
259 Posts
Beerman,

Good post, I have been thinking about this also. My question would there be much of a difference between the tranny you mentioned and a C-6? Would your calculations still be within reason? Thanks for the help.

Oh, sorry for hi-jacking...
 

·
....ehhh
Joined
·
931 Posts
I had 4.56 with my 35s,

Awsome setup for off road, in 4 low and granny, the truck would climb anything.
On this trip my passenger side locking hub fell out, and l was stuck in 2-wheel the whole time.


But on the highway it reved pretty high.
Need to take extra gas when you want to go wheeling very far away.

But also if you are going to only do a ring/pinion in the front once you go past 4.10 you have to buy the bigger carrier, (unless you also buy a locker or Ls that replaces the original carrier)
 

·
Registered
Joined
·
274 Posts
I just got my 4.56 gears, havent got them in yet. Im running 35's and on the freeway i have been shifting to 3rd gear going up hills, this should help me out. Also just got my detroit locker. :rockon
 

·
Building gold from crap
Joined
·
2,253 Posts
i was thinking, that usually it is 410's for 33's and 456 with 35's, 488's with 36 or bigger, and so on, with the E4OD anyways. but just thinking, the 456's with 33's might not be all that bad, the low end would be awesome, the engine would hardly be working around town, your around town gas mileage would be up. but on the high way, your gonna tach maybe a little higher and lose some top end speed, becasue of over taching, but, those with 32's and the e4od and stock 355's know that just trying to maintain highway spped can be a bear, it tachs too low, always needed to drop out of overdrive, it never seems to maintain a constant speed,

so i dont think 456's would be all that bad wioth 33's and the e4od.
but im no expert
 

·
Registered
1995
Joined
·
263 Posts
SquattyD said:
i have a weak 351m, C6 tranny, and 4.56....and I hate it. On the highway, it screams. If you drive on the highway, I would get 4.10s. If you rarely drive on the highway, I would get 4.56's. If you NEVER EVER drive on the highway, go with the 4.88's. Your top speed would be like 32 mph.
:histerica thats the top speed alright but you have to be going down hill go with the 4.10s
 

·
Charlie don't surf..
'92 Ford Bronco XLT
Joined
·
15,075 Posts
I was re-reading this post since I just ordered new gears for my rig. I wound up ordering the 4.56's since I plan on going to 35's at some point, right now I have 33's. I did some calculations based on what I've seen and also looking at the gear ratio chart here , this is what I came up with. With my current set up, 3.55 gears and 33's, I'm running right at about 2350 rpms at 65 mph, this is slighlty below the powerband. With the 4.56's and 33's at 65 mph the rpms will jump up to 3018 rpm which puts it right at the top of the daily driver/best overall performance spot. This is what I don't understand, the top of the chart says that with an overdrive tranny, which the E40D is, my rpm's will be 15% to 30% less than indicated, based on my calculation, that would mean conservatively I would be running around 2565 rpms at 65 mph. Does this make sense or am I figuring this out wrong? Thanks.
 
1 - 18 of 18 Posts
Top