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'67 coupe i6 to V8 rear end questions

997 Views 15 Replies 7 Participants Last post by  bmcgc
Hi there, in the process of converting my 67 for a v8 set up but I've been looking for what parts to get for my rear end and was hoping someone could help me out. as of this moment I have the complete rear end and I am curious on what I need, do I need new rear brake hoses, and do I need a new rear brake line? also will I be able to use the same parking brake cable? any help is appreciated guys!
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I did a 66 I6 to V8 conversion, so I do not know the 67/68 but can say...........look at the parts store (CJ Pony/NPD etc) catalogs and see if the part/parts that you are working with are I6 or V8 specific, of the same reguardless. As for the 65/66, the parking brake system was the same, no differences. As for brake lines and hoses, again look at the catalogs. Are you just doing a suspension/steering swap from I6 to a V8 only? It took me a while to do my conversion, I was driving it during the transition progress. I can also say.....if you are sticking with the I6 and you install V8 coils and suspension up front, the front end will sit a little high do to the weight of the I6 being less. Yes......it will make it handle much better with the V8 suspension setup with the I6 power, but again.....the front will sit a little higher. Are you planning on insalling V8 rated rear leaf springs?
 

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Discussion Starter · #3 ·
I did a 66 I6 to V8 conversion, so I do not know the 67/68 but can say...........look at the parts store (CJ Pony/NPD etc) catalogs and see if the part/parts that you are working with are I6 or V8 specific, of the same reguardless. As for the 65/66, the parking brake system was the same, no differences. As for brake lines and hoses, again look at the catalogs. Are you just doing a suspension/steering swap from I6 to a V8 only? It took me a while to do my conversion, I was driving it during the transition progress. I can also say.....if you are sticking with the I6 and you install V8 coils and suspension up front, the front end will sit a little high do to the weight of the I6 being less. Yes......it will make it handle much better with the V8 suspension setup with the I6 power, but again.....the front will sit a little higher. Are you planning on insalling V8 rated rear leaf springs?
so far all I've done are install the disc brakes and the next step is to put the rear in and then Im gonna be switching out some of the old steering hardware, im sticking with the same coil sizes and yes my plan is basically to get it prepped for when I get the 289. so for the meantime I am going to be sticking with the i6 and I have the V8 rated leafsprings too. I guess Im just lost as to what I should be buying, dont want to buy abunch of stuff that ends up being useless but Im pretty sure the brakeline needs to be changed and I think getting two rear brake hoses wouldnt hurt
 

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The 67 and later rear axles are a little wider than the 65-66, and even the 8 inch center section is a little stronger than the 65-66 with extra webbing in the cast iron making kind of a waffle pattern. There are plenty of used ones out there, from salvaged cars and from swaps to 9 inch axles where people were building for bigger power or swaps to IRS setups. The 8 inch is fine for any street driven small block. You can add an aftermarket locker if you don't find a factory Equa-Lok or Tru-Trac or whatever, or you can swap in a locker from any later 8 inch diff well into the late 70s, if you just have to leave matching marks on the asphalt. I think your steel lines from side to side on the axle tube will be fine, and there's only one rubber line from a steel line that comes from the front, and is connected to a tee on the top of the driver side of the axle. The hand brake cables should connect right up.
 
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Do you have a C4 or 3 speed?

On my 67 200 to 289 swap with a C4 the driveshaft is the same length but I need a new rear u-joint.

I'm using a 1970 8" out of a Mustang.

I seem to remember the 3 speed driveshaft is a different length.
 

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You will need to replace the rubber line from the steel brake line on the body to the axle. Even if it matches up you don’t want to be using a 50 rubber line on a critical part like brakes. You’ll want to basically replace everything from the backing plates out for the same reason. New pads, hardware, brake cylinders, and drums. If you want better brakes, Ford made a thicker set that you can install by changing out the backing plate. Open Tracker sells them. Good quality brake pads front and rear make a huge difference too. While you have the rear out I would replace the axle bearings and seals too. Cheap insurance.
 
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Hi there, in the process of converting my 67 for a v8 set up but I've been looking for what parts to get for my rear end and was hoping someone could help me out. as of this moment I have the complete rear end and I am curious on what I need, do I need new rear brake hoses, and do I need a new rear brake line? also will I be able to use the same parking brake cable? any help is appreciated guys!
You are asking for answers while not giving specifics which can lead to assumptions, and you know the rest.
The replacement rear end is from a what?
The ring gear size is what?
 

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To me, you answered your question......if you are going to convert to a V8, install V8 parts as you go. It also sounds like to me, you will be driving the car during the conversion process, taking a while to "get-er-done". I first started with the rear end, then the front end, and finally the engine and transmission. I do have this one piece of advise, on my conversion, if I had to do it again, I would have just bought a V8 car to start off with. Off the top of my head, I spent a good $6,000 PLUS easy, probably closer to $8,000 (kept the reciepts, but did not add them up to prevent myself from having a mental breakdown knowing how much this really cost me). I could have saved money and time, but I am not the type of person to just remove and install a used/dirty part or used dirty/not restored part. For the 65/66 there are great list / info on the forum what needs to be changed, so do a search for a 67/68 conversion and hopefully there is a good list to guide you. As bmcgc stated, since you have a C4, hopefully for the 67/68 is like the 65/66, in that the driveshaft is the same for an I6 and V8.......you have to do a little digging and searching the forum and maintenance manual.
 

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I replaced my entire brake system converting from 4 to 5 lug. The only parts I reused were the rear backing plates.

By entire, I mean the brake pedal all the way to the rear drums, every single part. I put Chocko discs on the front.

The 1970 8" had been sitting in a garage for years. I figured that at 50 years old I may as well change the bearings, fluid and seals.

I also installed the 5/16" V8 fuel line at the same time.

It wasn't that expensive, maybe $1500 for everything.
 
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Discussion Starter · #11 ·
You are asking for answers while not giving specifics which can lead to assumptions, and you know the rest.
The replacement rear end is from a what?
The ring gear size is what?
sorry im still kinda new to all this so I kinda dont know what to put. it's a 8" rear end that's in pretty good condition out of a 67 or 68 mustang
 

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Discussion Starter · #12 ·
You will need to replace the rubber line from the steel brake line on the body to the axle. Even if it matches up you don’t want to be using a 50 rubber line on a critical part like brakes. You’ll want to basically replace everything from the backing plates out for the same reason. New pads, hardware, brake cylinders, and drums. If you want better brakes, Ford made a thicker set that you can install by changing out the backing plate. Open Tracker sells them. Good quality brake pads front and rear make a huge difference too. While you have the rear out I would replace the axle bearings and seals too. Cheap insurance.
oh damn I'll have to give that a look then, i'll take any little improvement where I can especially with brakes
 

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Here is my writeup last time I did this, a couple years ago. It may help with a few questions, hopefully.

Resurrecting an 8 inch rear

I am a bit ahead of you on this project, as I am at the final stage of getting the 302 to it's first start soon. I did the same with replacing suspension and leaving the I6, but keeping it running along the way.
 

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Discussion Starter · #15 ·
Here is my writeup last time I did this, a couple years ago. It may help with a few questions, hopefully.

Resurrecting an 8 inch rear

I am a bit ahead of you on this project, as I am at the final stage of getting the 302 to it's first start soon. I did the same with replacing suspension and leaving the I6, but keeping it running along the way.
I will definitley be going through this! I really do appreciate the help!
 

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Nice writeup Brad, I did the same thing.

The only thing I would do differently next time is use steel brake lines instead of stainless steel brake lines on the axle. The SS is very hard to bend. Since my car doesn't get wet unless I get caught in the rain, the SS isn't necessary.
 
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