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Discussion Starter #1
I heard of a 5 bolt engine and bellhousing and a 6 bolt engine and bellhousing today. For 289 what are the application of these engines and bellhousing?
 

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Early 289s were 5 bolt and IIRC in 65 or after they ran out of 5 bolts Ford went to a 6 bolt block and bell. fd
 

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The Forddude is right. The original small block Ford, the 221 CID had a 5 bolt bell housing. Mustangs with the 260 and early 289s had the 5 bolt bell housing. Of course, the engines had that pattern as well.
 
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Discussion Starter #4
If for some reason the car needed to have a 302 put in it, is the 302 6 bolt?

5 bolt or 6 bolt is new to me. This sounds like it could be a headache for engine and transmission swapping.

Any input would be greatly appreciated as I know nothing about the differences.
 

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Yes. All small blocks built since sometime in 1965 have the 6 bolt bell housing.
 

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Actually, the 6 bolt blocks hit the streets in Aug/Sep 64.
 

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don't count the bolt holes across the bottom, they are for the dust shield to attach to. 5-bolt vs. 6 bolt is only for the trans to engine mounting points
 

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The earliest 6 bolt cast that I've seen was 4G23 -July 23, 1964

Steve
 
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Kenn, If you are talking about the bellhousing to trans bolt up, standard trans of course, this is for the early and later style transmission. This bellhousing was made so you could use either trany. The 5 or 6 bolts we are talking about are the engine to bellhousing bolts.
 

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No this one has 8 threaded holes, there are extra gussetts on the inside for these holes, the pattern is is closer to the center than the normal pattern that a toploader bolts to. I have never seen one of these before and just thought somebody might have a clue
 

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We can narrow it down better than "since 65" by saying August 64 :)
 

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Early 289s were 5 bolt and IIRC in 65 or after they ran out of 5 bolts Ford went to a 6 bolt block and bell. fd
Hey I’m new to this forum. My name is Ben. I have an odd question. I have an early 5 bolt 289 and I’m rebuilding it to put in my 66 Mustang. (Did not realize this entire 5 bolt vs 6 bolt thing) Getting rid of the c4 and putting in a 4 speed manual transmission which I have. I’m looking for a 5 bolt Bellhousing which is a struggle because my 4 speed has a wide bolt pattern. Can I use a 6 bolt Bellhousing it looks like I’d just leave one bolt out(still have 5). Maybe that’s a dump question. Or is there some adapter plate for the Bellhousing?
 

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No, you cannot attach a 6 bolt bellhousing to a 5 bolt block. The spacing between the bolts is completely different.
Most 4 speeds built after Aug, 1964 have both bolt patterns- the narrow pattern for the 5 bolt bellhousing and the wide pattern for the 6 bolt bellhousing. My '65 built in Sept '64 came with a Borg Warner T10 4 speed and it has both patterns.
If you are determined to use your 5 bolt block you will need to find a 4 speed transmission with both bolt patterns.
 

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No, you cannot attach a 6 bolt bellhousing to a 5 bolt block. The spacing between the bolts is completely different.
Most 4 speeds built after Aug, 1964 have both bolt patterns- the narrow pattern for the 5 bolt bellhousing and the wide pattern for the 6 bolt bellhousing. My '65 built in Sept '64 came with a Borg Warner T10 4 speed and it has both patterns.
If you are determined to use your 5 bolt block you will need to find a 4 speed transmission with both bolt patterns.
I appreciate the help. Not what I wanted to hear since I’ve rebuilt the engine but at least I know what I need to get now. Now I’ll just need to sell the c4 I’m replacing and get rid of the 4 speed manual one I bought and purchase a Ford Borg Warner T 10. Thanks for clarifying. Didn’t realize there was this issue until now.
 

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Both the BW T10 and Ford Toploader are available with the dual bolt pattern. Here's what you're looking for.
Dual Bolt Pattern.jpg
 

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What about an 8 bolt, I have an 8 bolt aluminum for a 289,any idea? 8 bolt at the tranny not the motor
That's for attaching to the early narrow pattern and later wide pattern. Has no direct relationship to the 5/6 bolt bell question, although the 5 bolt bells tended to have the narrow pattern.
 

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I appreciate the help. Not what I wanted to hear since I’ve rebuilt the engine but at least I know what I need to get now. Now I’ll just need to sell the c4 I’m replacing and get rid of the 4 speed manual one I bought and purchase a Ford Borg Warner T 10. Thanks for clarifying. Didn’t realize there was this issue until now.
Why would you "need" a T10? The only reason Ford ever used the T10 was because Ford Design transmission production couldn't keep up with demand. Both were used at the same time, interchangeably, and there wasn't even a difference noted on the warranty tag on the door, so there's no way to tell what a car had originally.

The Ford transmission is superior to the T10 in every way, with one notable exception. Early Fords, including in early Mustangs, had a 25 spline output shaft. These were prone to twist and break. I've seen them so bad that you couldn't get a slip yoke to slide onto them. These should be avoided at all cost. Typically, they have the narrow bolt pattern at the front, which makes them easy to spot.

764088


The later 28 spline shaft cured this problem.
 

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Both the BW T10 and Ford Toploader are available with the dual bolt pattern. Here's what you're looking for. View attachment 764086
I believe then I have a BW.
So at the risk of sounding like an absolute novice but swamping our this c4 for this top loader transmission has been more complicated than I anticipated. This the transmission I have. Are you saying that I could bolt the bell housing I have pictured below to this one? I don’t have that bell housing yet but I could purchase it.
764087

I could buy this one so I think I’m ok? If that’s the case I’m back on track with my project.
764089
 
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