I have a chance to buy a nice mustang 9" rear end with 3.55 gears for $200 dollars. It is in great shape and will fit under the maverick without modifications. I also already have a set of disks that I can run on it. I will eventually run a AOD transmission but for now I have a C4. My question is would it be wise to run the 3.55 gears before I get the AOD or would this raise my RPMs at highway and kill my MPG worse than it is? I do a decent amount of highway and city driving in the maverick. Thanks guys!
It will raise rpm's at highway speeds; If MPG's is critical, I'd wait till I go AOD. Also, If I were not putting some serious rwp down and doing a fair amount of drag racing - I'd put the 3.55's in the 8" housing. JMO...
If you currently have an 8 inch rear, you will have to shorten your drive shaft once you install the 9 inch. I think the stock drive shaft is 46 1/2". Not sure about the overall length between the C4 and AOD, if they are both the same, then you would only have to shorten the drive shaft once. The drive shaft I have is 45 5/8" using the short 1310 pinion yoke on the 9 inch (there where only 2 lengths, a short and long yoke), behind a Toploader 4 spd. which should be the same overall length as the C4? Regarding your MPG, what gears are you currently running? I have 3.70 and at 60 mph, I am turning 3000 rpm.......... David
That is what I figured. I currently have a 8" in there now but I am pretty sure at one point in its life somebody abused it and it will eventually need a full rebuild. On the other hand I can go with the 9" which is in great shape and if I ever decided to add more power it will be more than able to handle it. That is my thought process right now. I could also sell the 9" later on and easily get my money out of it I think.
For $200.00 for a 9" that will fit the Maverick is a great deal, you could always change out the gears if you dont like the rpms it is running at.
That's true. I believe the AOD is actually a bit longer than the C4 so it would make sense to wait. Currently I have a 8" with 3.00 gear. At 65-70 mph I am turning about 3000-3100 rpm.
That's what I was thinking also! The guy who currently owns it used to build high performance mustangs and he had a few rear ends left over. He actually wants $250 for it but we are going to do $200 and a small trade. I figure at the end of the day if I don't like it I can always sell it and easily get my money back... I usually see 9" going for $400-$500.
If you got a place to store it would snatch it up and at least put it up for now. Is this 9" unit 28 spline axles or 31 spline? That will have to be taken into consideration if you swap the third member.
That seems like a lot of rpm for those gears, must have short tires on it or is that just the nature of these cars to run that high of rpms. I have installed two nine inch rearends and never had to shorten driveshaft
To be honest I am not sure. I will be taking a closer and more detailed look at it tomorrow and will make the final decision if I want to buy it.
That is great to hear! That will save me some money down the line. I was thinking I might have to have a custom drive shaft made.
They are only 14" rims. They are not especially tall tires, they are the factory mags for the car. When I swap out the trans and rear I will throw a set of aluminum 15" rims on the rear that are a similar style to the front.
There are two factors for determining engine RPM, tire height and gear ratio... Makes no difference if were are talking Maverick or John Deere tractor...
I had the same rims with 60 series tires and running a 4:00 gear ratio and my rpm is just slightly higher (3,500) at those speeds. It is interesting when looking at charts that tell you rpm with different gears and tires heights. It is unnerving driving on the freeway at those rpms I like you can see an AOD in the future
