My wife's cousin's uncle (confused yet?) is GIVING me a 289 HiPo and the C4 trans that was mated to it. I will have to get the motor dipped and put back together, but that's not a biggie. My question is when I go to do the disk break conversion do I have to buy new axles for the rear or is there a way to swap that to 5 lug without replacing them?
Also, should I replace the 6 cyl rear end or just change the pins in the gears?
Nope, sorry that is why a 6 to 8 conversion is so expensive. You have to replace the driveshaft, the rear axle, the brakes, wheels, wiring, and suspension to withstand the extra weight and power of the V8.
Give this a reading Six Cylinder Upgrade V8 - Mustang & Fords Magazine Cheapest way to do the front is Welcome to CSRP the rear end is a 7.5 a v8 will break it you need a 8 inch.Most spend about 3 grand in parts just to swap all the v8 stuff not counting the engine or tranny.Cheapest way is sell your car and buy a v8 one or get ready for a lot of fun changing everything over.
Ok dude, it's not as hard as people are making it out to be. I have done this swap several times, and there isn't much to it at all. The only thing you must change out in the swap is the motor mounts. Everything else will work fine. The rearend, gears, driveshaft, suspension, etc. There is nothing wrong with keeping that stuff for a while and doing the other stuff as you can. If you want to change to 5 lug however, you do have to change some stuff. In a 6 cyl, you have a 7" rearend, so you have to change it to an 8" or 9". To my knowledge they don't have axles to change out in that rearend. They may have some type of adapter though, but I question the safety of adapters. The suspension in the back and the driveshaft will bolt right up to whatever rearend you get, and there are plenty of used ones around. The only problem with the front, is that in a 65 you have to change the spindles to go to the 5lug brakes. In 65 and 66 ford made them different sizes, but in 67 and up they are the same. The 6cyl suspension will handle the 289 just fine. There isn't much difference in weight, but it my be a little soft. Most likely, if it hasn't been done already, you will need new front suspension anyway. Just get v8 springs instead of 6cyl springs. They are the same price and there is no modification needed to put them on. If you go to 5 lug, there are used spindles around also for cheap.
For used parts a good place to look is Larry's Mustang Supply in Moulton, AL. He is a great guy and will help you out with what you need.
P.S. A v8 will not break the 7.5 inch rearend because it won't hook. I had a high hp 351w with that rearend for years with no problems. If the rearend won't hook, it won't break. I have however broken a rearend with a 6cyl that didn't have enough hp to break the tires loose.
Keving is right, I am actually in the middle of this swap as we speak. The only difference is that I am starting on the suspension and I don't have a motor yet. I replaced the 6cyl rearend with a 8" and put 3.25 gears in it. I replaced my old leaf springs with mideye 4.5 leaf springs (something you might want to think about). The old driveshaft bolts right up just be sure to replace the old u-joint. Dennis at www.discbrakeswap.com sells a very affordable front brake conversion kit that comes with new spindles and a power booster if you want it.
If you want to change to 5 lug however, you do have to change some stuff. In a 6 cyl, you have a 7" rearend, so you have to change it to an 8" or 9". To my knowledge they don't have axles to change out in that rearend.
Do you mean that I'm stuck with a 4 lug rear end? Wasn't a 5 lug optional in 65?
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Originally Posted by Keving
They may have some type of adapter though, but I question the safety of adapters.
Wasn't really wanting to go the adapter route either.
Quote:
Originally Posted by Keving
The suspension in the back and the driveshaft will bolt right up to whatever rearend you get, and there are plenty of used ones around.
Good news for me here. I was worried about this!
Quote:
Originally Posted by Keving
The only problem with the front, is that in a 65 you have to change the spindles to go to the 5lug brakes. In 65 and 66 ford made them different sizes, but in 67 and up they are the same.
Doesn't the conversion kit from diskbreakswap.com come with new spindles?
EDIT: I didn't see the post below your's until after I replied.
Keving is right, I am actually in the middle of this swap as we speak. The only difference is that I am starting on the suspension and I don't have a motor yet. I replaced the 6cyl rearend with a 8" and put 3.25 gears in it. I replaced my old leaf springs with mideye 4.5 leaf springs (something you might want to think about). The old driveshaft bolts right up just be sure to replace the old u-joint. Dennis at www.discbrakeswap.com sells a very affordable front brake conversion kit that comes with new spindles and a power booster if you want it.
Thanks. The motor is in pieces right now, it needs dipped & honed before I can do the install. I actually plan on getting all of the body stuff done before I do the swap, so I'll probably be doing the break upgrade first as well.
You can get 5 lug but have to swap the whole rearend to an 8" or 9". I have a 9" out of a Cougar in mine. It bolted up with no modification. there is a guy in washington state that has a ton of them for cheap. You can't get 5 lug axles for the 6cyl rearend though.
According to 66mustang12b that brake kit does come with spindles. I have a 68 which 6cyl and 8cyl spindles are the same, so I didn't have to worry about that one. I don't know anything about the kit he is suggesting.
I am not saying this to be rude, but really am I the only one who has a working GOOGLE site. If you type Mustang V8 Swap into Google you get page after page answering all these questions most of them pointed to the other 700 threads on this site where the same question has been asked.... Every two days we have a new "How do I put a V8 in a 6 cylinder thread"
Sorry just felt like venting....
__________________
Mike
I've had 60 cars....most of them Mustangs :-)
Yeah the 5 lug rear end is a 8inch or 9inch both v8 cars had the inline6 used a 7.5 which is the 4 lug.Its not a hard swap just a lot of parts and most get pricey once you buy everything.And btw you can break a 7.5 with a v8 i did it in a 82 crown vic with a 351w in it.That kit is a ford granada swap but he remakes the spindles to match the mustang so no bump steer problems.67-70 they used the same spindle 71-73 they all went 5 lug.
My wife's cousin's uncle (confused yet?) is GIVING me a 289 HiPo and the C4 trans that was mated to it. I will have to get the motor dipped and put back together, but that's not a biggie. My question is when I go to do the disk break conversion do I have to buy new axles for the rear or is there a way to swap that to 5 lug without replacing them?
Also, should I replace the 6 cyl rear end or just change the pins in the gears?
I am currently working on a six cylinder conversion. I know I'm just 22 but I know this car like the back of my hand. The six cylinder components WILL work for the start. If you can pick up V-8 spindles and 8 or 9 inch rear end, do it!! I have manual steering on mine....and all the V-8 components connect to the six cylinder spindles. However, I'm currently connecting the V-8 spindles and rear end I got from Classic Ford. It's not that expensive to do the change. The reason why this car was not sold to buy a V-8 Stang is cause of the history. My motor cost me $2800, tranny $650, spindles/brakes and rear end/third member $750, front end components (including frame brackets) $600, shocks all around $130. The car it's going in has very little rust and the original seats, console, and dash are in awesome shape. Being that you have an engine to work with.....you're off to an awesome start!! A 289 Hi-Po with solids.....I would give my left arm for that.
Advice on motor swap... 
I will have to get the motor dipped and put back together, but that's not a biggie. My question is when I go to do the disk break conversion do I have to buy new axles for the rear or is there a way to swap that to 5 lug without replacing them?
Every two days we have a new "How do I put a V8 in a 6 cylinder thread"
