Car is a '65 with the original 289 / C4 setup.

I was hoping that it was the oil pan gasket leaking at the back but after replacing the pan gasket the leak is still there. So it is the rear main seal leaking - no surprise since it is as old as the car.

Plan A: Pull 289 motor and replace rear main seal, put 289 motor back in car.

Plan B: Pull 289 motor and replace with a built up 302 spare motor that I picked up. What I want in the long run is a reliable driver with a little lope in the cam. Nothing wild or stroked since I will be spending money on the other Mustang this fall.

Anyone else been in this position? Insights ???

 

Make sure that your intake manifold is not leaking out the back, if so, it will look like a rear main seal leak unless you check right at the back of the intake...

Also, you have another option,,, you can replace the main seal with the engine in the car, which is what I would do if I were in your shoes...

 

+1
I just did this Yesterday. Pull the cross member and disconnect the pitman arm and the pan will come out. Remove the #5 main CLEAN EVERYTHING and put the new seal in place. I used the FEL PRO silicone seal. Torque to 70 foot pounds in 3 stages. The hardest part was getting the oil pan back on , its a little hard to glue the pan gasket in place then place the pan up an bolt it down ( darn gravity) . Make sure you have a helper to hold the pan.
This really only took about 3 hours in my garage and I only needed air to remove the cross member.

 

After removing the #5 Main how do you get the seal around the backside of the crank? Is it a rope seal or a rubber seal?

 

They make a tool to remove the rope seal, called "jake the snake",,,, it screws into the rope seal and pulls it out. If the engine has the rubber seal, it will come out easy enough..

rope or rubber?? If someone has been into the engine in the last 20 years it is probably rubber...

If it is rope, there will be a small pin in the cap that will need to be removed to replace with rubber.

LOL Ok, so it is not called "Jake the snake",, it is a "sneaky pete" the "sneaky Pete" tool is still available (Lisle). Link with pic.

Outdatedlink = try this one http://www.usatoolsinc.com/index.asp...=GO&Page=1


https://mustangforums.com/m_3226155/mpage_2/key_/tm.htm