Replacing a 11 1/2 Clutch with a 12 inch

[pchelp101]

Has any replaced their Big Block Ford OEM 11 1/2 with a 12 inch clutch kit? Did you have to replace the flywheel?

[Lee]

Hi,

Many years ago I replaced the clutch in my 1970 F-250 with a 390. Here is the kit I used. It is a 12" disk. I also replaced the flywheel as it was damaged from overheating. I did not specify that I needed a plate for a 12" clutch when I bought it so,... wondering if the mounting bolt pattern is the same for either 11 1/2 or 12 inch pressure plate.
https://www.carid.com/rhinopac/premium- ... -050a.html

Interesting, when I look at the Vehicle Fitment section of that website... it states that this clutch kit is used for mostly mid-70's to early 80's trucks with either a 460 or 400M engine yet it also shows it fitting a 1967 Mustang with a 390. It fit my 1970 F-250 just fine... In fact I have about 45k miles on it and it's still holding well.

Also, the local O'Reilly's offers a 12" clutch kit.
https://www.oreillyauto.com/shop/transm ... ford/f-250

Take care,
Lee

[pchelp101]

Hi,

Many years ago I replaced the clutch in my 1970 F-250 with a 390. Here is the kit I used. It is a 12" disk. I also replaced the flywheel as it was damaged from overheating. I did not specify that I needed a plate for a 12" clutch when I bought it so,... wondering if the mounting bolt pattern is the same for either 11 1/2 or 12 inch pressure plate.
https://www.carid.com/rhinopac/premium- ... -050a.html

Interesting, when I look at the Vehicle Fitment section of that website... it states that this clutch kit is used for mostly mid-70's to early 80's trucks with either a 460 or 400M engine yet it also shows it fitting a 1967 Mustang with a 390. It fit my 1970 F-250 just fine... In fact I have about 45k miles on it and it's still holding well.

Also, the local O'Reilly's offers a 12" clutch kit.
https://www.oreillyauto.com/shop/transm ... ford/f-250

Take care,
Lee

Thanks Lee, on another blog site someone else tried switching to the multi-finger pressure plate instead of the OEM lever type. He had clearance issues when trying to resemble the transmission. You must have totally lucked out with the flywheel because the new flywheels all come "weight balanced" and they don't work with the internal balanced FE 390's. They start to vibrate and shake like they are coming apart.

For now I found a local fabricator that is going to resurface my OEM flywheel and rebuild my 11 1/2 inch pressure plate and clutch disc.