[rocky50]

I have:
85 F150 orig. owner.
Swapped out 300/6 for 95 302 HO crate.
AFB, recurved dist. MSD 6al.
3-sp auto that came w/the 6. (C4/5?)
3.08 rear end.
I've got to do something w/ the rear end ratio. It's a real dog from a dead stop. At first I thought about a 4.11, but I think that would give me very bad gas mileage, while i'd be waiting awhile for a AOD. I'm thinking more along the 3.50 range. Can't find a whole rear end locally so I'm gonna have to change the gears myself. Can this be done without pulling the entire rear? This is a street truck, no drags but i'd like to leave a stop light quicker than my 30yr. old Porsche..

 

[Dave C]

What type rear end is it. 9" or 8.8". From the 3.08 I would guess that it's the 8.8. If that's the case a set of 3.55's would work well.

I just sold my my 92 F 150 w 302/AOD. It had 3.55's from the factory as part of the factory towing package. You might look for a rear from one of these trucks. (92-96 302/351 F-150) Or you can get a set of new gears. Since you have a 3 speed auto I wouldn't go any lower if you do much highway driving. If it's mainly for around town the 3.73's would also work.

Later,

David Cole

 

[rocky50]

Say Dave,
What RPM were you turning w/ the 302/AOD/3.55 at 70MPH?
I guess I'll have to check the Pensacola bone yards, cause I'd rather change the whole rear than just the gears.

Thanks.

 

[Dave C]

I don't really know what rpm it was turning. I never put a tach in it. It wasn't a hot rod. I have my 69 Mustang for that.

An educated guess says about 1900-2000 rpm at 65 on the highway. Keep in mind that this was with an AOD auto. That 4th gear overdrive dropped the revs quite a bit. Also had 30" tires. The guess is based on the 5.0L Mustang I used to have. It turned 1600 rpm at 60 mph with 2.73 gears and 26" tires. The taller tires partially make up for the 3.55's.

Later,

David Cole

 

[CantDrive55]

My 90 F-150 AOD with 3.55 turned about 2100k at 70mph.