I was thinking of converting my 65 Tbird to a dual mastercylinder. Could I use a 1967 dual mastercylinder without adding a compensation
valve? Has anyone done this type of conversion?

I did this to my '66 using the '67 master cylinder. You will have to modify the brace from the shock tower to the firewall for clearance. The new master cylinder hits the brace. I removed the part on the shock tower that the brace mounts to and rotated it towards the front of the car and redrilled it, then added a transition piece to join the 2 parts together. If you don't have a spacer between the master cylinder and the booster you can notch the brace and get enough clearance. I saw a '65 that the guy did that. Just make sure you adjust the rod that goes into the master cylinder per the instructions that come with it. If not adjusted properly the brakes will hang up. Take if from someone who knows.

To Marchij: Did you have to use a poportioning valve when you changed to the dual master cylinder? Also what about the brakes lines? Did you have to change any of the existing brake lines? Someone told me to use permatex thread lock on all brass fittings to prevent air from being sucked into the system. Any help you may give me here would be gratefully appreciated.

Derek,
No proportioning valve is needed. You already have it in your present system. You may have to run new lines from the existing blocks to the master cylinder, you will have to check to see if the existing lines can be bent to fit the new master cylinder. I installed all new stainless lines from front to rear including the lines on the calipers and the lines to the master cylinder. I didn't use anything on my threads. They seem to be Ok.

Marchij,

Thanks for all the information. I may attempt to convert the master cylinder over the winter months. I may have to change the brake lines if they dont fit. Were you able to buy the exact lengths of stainless steel brake lines or did you have to have to cut them to fit properly? Were you able to buy a new mastercylinder for a 67 Tbird? I think most of the ones I saw for sale were rebuilt. I guess the wheel cylinders would also have to be changed on the rear brakes if the brake lines are seized at the connections. Thanks for the information.

I think I got pre-formed brake lines from Classic Tube. They advertise in Hemmings. I also could not get a new master cylinder, I was told they are not available, so I got a rebuilt.