Rear End Job

[jisham]

I was curious - am working on the specks for my rebuild - what all is involved (i.e. costs, and axel, etc.) in redoing the rear end of a 200 i6 '66 Mustang.

I was told by someone that I might as well drop in a 289 because I will have to redo the rear end anyway if I hop up the 200 i6. Any thoughts?

 

[GrantD]

I can't comment on the whats all involved, but that has to be one of the poorer reason that anyone would consider putting in a v8. There a lot of decent reasons to put in a 289 (cheaper power), but I don't see how anyone could justify the thought that the swap somehow makes way more sense now that the stronger rear end is in. One other thing and I'm sure many on this forum will agree, is that for as long as you drive a straight six people are going to ask why/tell you to put in a V8.

I'm sure someone will come along and answer your specifics, there are a lot of guys that run cars quicker than the stock 302, 289's around here.

 

[Shrinkdude]

Well if you put a 289 in then you need to upgrade the front suspension to a V8 as well.
There are 7.25 rear parts still available from the parts stores, so you should be able to get the basics like bearings and seals. I have seen some stuff on ebay for that rear as well. There are shops out there to rebuild it for you if you want.
Just because you put in a 8" or 9" rear doesn't mean you have to upgrade to a V8 as well. I bought an 8" off ebay and plan to rebuild it and put it in but keep my six. I also plan some time in the future to upgrade the front suspension too. I like the fact that mine is a straight six and not a "me too" V8 car. Just my opinion.

 

[jisham]

Another concern the guy had, he is helping me because he has the experience rebuilding cars, was that the block might be cracked - I figure I should at least take then engine out and determine if that is the case before I toss the 6 out the window.

I also am kinda into keeping things original as well as unique. So I kinda want to stick with the i6, just to say I made what I had work...really well. Anyway, I also figured I can do the V8 thing later when I get a mustang that was made for a V8.

Then new FSPP head also looks like a lot of fun when it is released.

 

[LaGrasta]

great site and really the best way to go unless you're looking for a 100% concours restoration.

http://www.redfalken.com/pages/rearend.html

 

[JackFish]

I think you've been getting advice from someone who has knowledge of 289s, but has no experience with I-6s. It's their comfort zone.
"might have a cracked block" - based on what?
If the rear isn't broken there would be little reason to swap it until it is.

 

[Funky Cricket]

these blocks are about the toughest things on the road. doubt it has a cracked block unless it was really REALLY neglected. And you can get a replacement block really cheap.

I say stick with the 6. it is original (to the car AND not a v8) and a fun engine to own IMO.

and you can get 8" swap parts pretty easily, check the for sale and your local junk yard.

 

[CZLN6]

Howdy Kisham and All:

The stock 200 rearend is typically a 7.25" Salisbury with an integral carrier- which means that it is part of the axle housing. These rearends are hell for tough behind a 200 six- unless, they have been allowed to run dry of lubricant, due to a pinion seal leak. Symptoms of a badly worn differential is howling and/or whining. They seldom break all at once, but gradually worsen over time.

What are it's symptoms? Are you sure it is not a noisy wheel bearing(s), which have the same noisy symptoms? Small U-joints on these rears are also susceptiable to rapid wear from abuse.

If you're happy with your current gearing and are no expecting much abuse, I'd suggest you assess the 7.25" and repair as needed. If you want to have fun, swapping to a 289 is more trouble than it is worth.

What are your long term plans for this car?

Adios, David