Used Center Section/Third Member
Thread Starter
|
More Turbo
Joined: Nov 2004
Posts: 646
Likes: 0
From: Cleveland, TN
Used Center Section/Third Member
I found a 9 inch Center Section for my 86 F-150, the reason im replacing it is because i have an open rear end right now and i want posi......the guy that selling it to me says it has 3.90 gears.....how much worse will my gas mileage be????? BTW i have a 302 EFI and a granny gear 4 speed
Thread Starter
|
More Turbo
Joined: Nov 2004
Posts: 646
Likes: 0
From: Cleveland, TN
no it doesnt have an 8.8, it came from the factory with a 9 inch...i guess its pretty rare...and i just found out that it has 31 spline axles......one more question, how much do think 3.50 gears will affect gas mileage??
Lead Driver
Joined: Oct 1999
Posts: 6,779
Likes: 556
From: Kalispell, MT
Ford used both rears in '86. My '86 4x4 302 EFI has a 3.50 9" rear and I've averaged 15-16mpg for the last 15 years (312,000 miles) but I have the 4spd OD (TROD - I think) transmission. I finally got rid of my limited slip rearend about 5 years ago when the side gear/axle spline stripped for the second time. Just dumped in an open 3.50. It's a decent all-round rearend. You won't do quite as well with a 1:1 tranny.
With a granny low 4 spd, I'd try to come up with something in the 3.00-3.25 ratio range. If you have to you can use 1st to get it rolling. You want to come up with something that will keep your rpms under 2000 at cruising speed.
With a granny low 4 spd, I'd try to come up with something in the 3.00-3.25 ratio range. If you have to you can use 1st to get it rolling. You want to come up with something that will keep your rpms under 2000 at cruising speed.
Last edited by mtflat; Dec 27, 2004 at 10:48 PM.
Thread Starter
|
More Turbo
Joined: Nov 2004
Posts: 646
Likes: 0
From: Cleveland, TN
Trending Topics
Lead Driver
Joined: Oct 1999
Posts: 6,779
Likes: 556
From: Kalispell, MT
totally depends how you drive 
Get grandma to give you driving lessons, maybe? I'd say something in the 12 range sounds reasonable.
What have you been getting for mileage and what gears do you have in it right now?
Get grandma to give you driving lessons, maybe? I'd say something in the 12 range sounds reasonable.What have you been getting for mileage and what gears do you have in it right now?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Thread Starter
|
More Turbo
Joined: Nov 2004
Posts: 646
Likes: 0
From: Cleveland, TN
im not exactly sure on my gears right now, but i think theyre somewhere in the 2's.....but i can handle 12mpg, and im gettin a new exhaust system and im sure that will help a little....so thanks for the info, im probably gonna get 3.50's sometime in the future