Hello, I have a 1965 mustang with a 5 bolt 289. I am currently trying to gather parts to swap out the c4 for a four speed toploader. I was wondering if I can buy any toploader (close or wide ratio) and have it bolt up to my 5 bolt manual transmission bell housing. I already have the bell housing and spacer plate however I do not want to buy a toploader that will not bolt up. Any help with this is greatly appreciated. Also The car was originally a 6 cylinder car and it still has the original driveshaft and rear axle. Will a toploader line up with a 6 cylinder driveshaft? I am hoping the v8 cars had the same length driveshaft as the 6 cylinder cars. Again any answers or help is greatly appreciated.
5 Bolt 289 Toploader Conversion
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For your model year (and most others too) the 6 cylinder mustangs had a smaller diameter driveshaft (2.50") than the V8 powered mustangs received (2.75"). That may not sound like much of a difference but it was for good engineering reason. Driveshaft lengths, U-joints/yokes and flanges all differed depending on application. Also, the size of the rear ends varied too depending on engine size and type with the V8's more robust with larger ring gears. Then there's the whole 4 lug vs. 5 lug difference between the 6 and 8 cylinder cars to consider as well. There were many engineering application differences Ford saw fit to make between engine sizes and these are but some of them. Sorry if I'm not really answering your questions all that well but if you didn't know these things you should. You will receive some great advice for solutions here, and Welcome to VMF!
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I believe the 5 bolt bellhousing uses the narrow transmission bolt pattern. Not 100% sure, however later manual transmission typically have both patterns on them. So now when you get the bellhousing you'll be aware of this. As stated you will need a new driveshaft and a new rear axle. Look for a 65-66 8" axle. The 67-70 8" will fit but it is 2" wider which may make wheel selection problematic depending on width and offset. The 17x8 99-04 wheel fits perfect with this axle. Another choice that may be easier to find is a 8" out of a 75-81 Granada. It's something like 1" narrower but otherwise pretty much ideal. For a driveshaft, get a 94-01 Explorer 4 door 2WD. They're aluminum and the right length.
Thank you for your replies. I was mostly just trying to make sure that a four speed toploader would bolt up to a 6 cylinder driveshaft and rear axle. I was wanting to install the toploader this summer and then over the winter take the driveshaft and rear axle out and convert the car from 4 lug to 5 lug. From your replies it seems that a four speed toploader will bolt up, but it is not ideal for reliability reasons.
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What you will need to figure out is if the length of the toploader is within a 1/2" or so of the length of the C4.
If it is not, then your driveshaft will not work.
If it is, then your driveshaft will work.
65/66 Mustangs use a 57.25" wide rear end.
Fox Mustangs use a 57" wide rear end 7.5" or 8.8".
The Fox 8.8" can be had fairly inexpensively, most had 3.08 gears, but there were some 2.47 and 3.27 gears that were also used., The control arm brackets have to be cut off and spring seats welded on. Right side Ranger axles and drum brakes swap over to give you 5 lug drum brakes.
If it is not, then your driveshaft will not work.
If it is, then your driveshaft will work.
65/66 Mustangs use a 57.25" wide rear end.
Fox Mustangs use a 57" wide rear end 7.5" or 8.8".
The Fox 8.8" can be had fairly inexpensively, most had 3.08 gears, but there were some 2.47 and 3.27 gears that were also used., The control arm brackets have to be cut off and spring seats welded on. Right side Ranger axles and drum brakes swap over to give you 5 lug drum brakes.
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Yes, the 5 bolt bellhousing uses a narrow Toploader pattern. It's not an issue of close vs wide ratio, it's an issue of the bolt pattern. If you get a narrow pattern Toploader (HEH-G, if I recall correctly), then you'll have no trouble bolting it up at all and everything will go together fine. If you get a wider later-year Toploader that wasn't originally bolted up to a 5-bolt motor, you may have an issue with the bellhousing. You might just be able to drill it out to fit the wider Toploader bolt pattern, but I seem to remember that the flange on that bellhousing isn't wide enough to let you drill it out the wider pattern.
I have a 5-bolt drivetrain in my car. At one point in time I needed to swap out motors and put in a 6-bolt with a 6-bolt bellhousing, which I then had to machine with the narrow pattern for the narrow pattern Toploader. Then it wanted a different bearing retainer, different clutch fork, etc. etc. I think doing it in reverse (5-bolt motor and bell with later Toploader) might be easier but that's entirely contingent on if you can machine the bellhousing to accept the wider mounting pattern.
Here's the 6-bolt bell I was using machined with both the wide and the narrow pattern, for your reference - so you might want to take a look at your bell and see if it has enough material on the upper flange to move the bolt holes a few inches outboard.
![754938]()
Of course, if you can find a narrow pattern early Toploader, then you won't have any problems and it'll all go together fine.
This page has a lot of really useful information: Ford Transmissions
And this page tells you which tag numbers have the narrow bolt pattern or not: Toploader id
I have a 5-bolt drivetrain in my car. At one point in time I needed to swap out motors and put in a 6-bolt with a 6-bolt bellhousing, which I then had to machine with the narrow pattern for the narrow pattern Toploader. Then it wanted a different bearing retainer, different clutch fork, etc. etc. I think doing it in reverse (5-bolt motor and bell with later Toploader) might be easier but that's entirely contingent on if you can machine the bellhousing to accept the wider mounting pattern.
Here's the 6-bolt bell I was using machined with both the wide and the narrow pattern, for your reference - so you might want to take a look at your bell and see if it has enough material on the upper flange to move the bolt holes a few inches outboard.
Of course, if you can find a narrow pattern early Toploader, then you won't have any problems and it'll all go together fine.
This page has a lot of really useful information: Ford Transmissions
And this page tells you which tag numbers have the narrow bolt pattern or not: Toploader id
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Except for "early" Toploaders the majority are drilled for BOTH narrow and wide mounts.
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Since your car already had a C4 in it, you almost certainly have the C5ZZ-B slip yoke, which will fit your 28 spline 4-speed. You may not even need to alter the length. Later, when you get a V8 axle, have a proper V8 shaft made.
Avoid the narrow pattern 4-speed, they typically had a 25 spline output shaft, and it just wasn't up to the job, I've seen 289 2V engines twist that shaft. A real POS.
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Huh! I didn't know that but that is good to know. That will certainly save some effort then.
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