Hello,
I am a new member and I was wondering if anyone can help me with info on a 289 to 390 FE swap in a 1967 mustang coupe. The 390 and cruise-o-matic came out of a 1966 tbird. I don't think that it would be too hard to do since they came with this motor stock. And "the question" of 8" or 9" diff. If anyone has an opinion.

 

you will need to find the motor mount brackets and a 9 inch, the torque of a 390 will rip a 8 inch apart

 

I have the same swap (66 T-bird) in my 69 coupe. In addition to the frame mounts, you'll need the correct rubber isolators and block plates. I've seen the plates for about $80 and the isolators usually show up on Ebay for about $100/pair. The transmission cross member is specific to big block/C6 and can be had for about $80 used or from a decent Mustang parts supplier. Here's where it gets sticky. To make the FE fit in the unibody cars, Ford used special "GT" exhaust manifolds. They must be used with "GT" heads that have a different exhaust manifold bolt pattern. 66 T-birds didn't come with "GT" heads. Most standard FE heads can be drilled and tapped for the "GT' manifolds. The manifolds are pretty common on Ebay and usually go for about $250/pair. Hooker does make headers with a dual bolt pattern that allows you to use the standard heads. I have them in my car and have had constant header leaks to the point that I plan to go back to stock manifolds. The radiator and shroud must be changed also. As for rears, don't even think about an 8", a 9" is the way to go with the torque of an FE. I hope this helps.

 

Thank you for the great info!!! I also was wondering If my Cruise-o-matic is a C6? And if the 9" in a 1966 tbird is close enough in dinension to put in my mustang ( 1967 coupe ) Or will it cost more to modify the 9" than to find a 9" out of a mustang at a swap or something.

 

I got my 9" out of a 69 Cougar and I'd recommend that you try to find the correct width. Here is some info on the rears: http://dfwmotorsport.com/Fairlane/9inchrearends.htm One more thing, you don't have to use big block frame mounts, You can use small block mounts if you drill another hole to change the angle they sit at.

 

I have found the engine plates and the isolators and bought them on ebay. It looks like they will bolt right on the small block frame mounts. Where do I need to drill another hole? It looks like one bolt goes through the isolator and the frame mounts. The same as when the small block was in it.

 

Man you are gonna have some fun with that!!! Just dont wrap it around a tree or pole.. Congrats!

 

I plan on doing the same swap as soon as I am ready to take my cruiser ( 1968 GT 500 KR clone ! ) off the road for a little while. Through all my online tech helpful info I have found you will DEFINITELY need to change your front springs as well due to the weight. Keep us posted as to how it goes. Thanks.

 

The hole gets drilled in the chassis mount and changes the angle that the mount sits in the frame. I did mine by comparing pictures of small block mounts and big block mounts. I think a guy on on of the other forums has a template. I'll see if I can find it for you. What's your plan for heads/exhaust? Another thing to consider is the shock towers. BB cars have a reinforcement welded at the lower portion of the tower. It's a fairly easy job with the motor out.

 

For the heads and exhaust I would like to go with GT heads and headers. Then an exhaust system for a 1967 mustang 390 out of maybe jegs or summit racing. They seem to have the best prices. I would be very happy if you could find a template. I heard about the stock towers too I will have to look into that as well. Also I heard the export braces need to be changed. Thanks again !!!