I was going to mill .170 off the piston on the front drum to add an extra clutch, but after doing some measuring I have noticed that it would eliminate the two small outer ears on the piston. Is this going to cause a problem? First time rebuilding and upgrading a BB 727. It has a 4 disc drum and I want to put in 5. It is 1977 Tranny.

Instead of machining the weaker aluminum piston, step machine the thick outer pressure plate as shown in the picture.

That won't weaken the pressure plate to much?

.170 is a lot , why are you taking so much off ? What clutch thickness are you using , what thickness snap ring .

Also you can step mill the pressure plate but that is taking more than half of it off (if I remember right)

Here is a pic of the machined pressure plate. You can also do the following:

** Machine some off the aluminum piston and some off the plate, use a 0.060" snap ring. Double check all your clearances before machining.

** Use a forward clutch inner pressure plate turned upside down. May have to clearance (remove) some of the raised section.

** Use thinner clutch frictions from A&A or CRT. You may be able to install 5 without machining anything.


www.aandatrans.com

www.coperacingtrans.com

http://www.aandatrans.com/Products/727-Direct-Friction-Red-Racing-Checkered-Thin__22595B-5.aspx


John