Another question concerning a 1958 3.4 engine into my 1967 340. The flywheels from both engines measure the same and have the same number of teeth on the ring gear. The difference is the locations where the pressure plates bolt on. The early flywheel is machined to accept a 10" pressure plate and clutch while the later one is 9.5". Can I use the early flywheel and 10" clutch for my all syncro gear box or must swap flywheels?

 

You would do better to change flywheels as long as the tooth count on the ring gear is identical. Your newer flywheel is likely drilled to take both ~ many are. The 9.5" diaphragm clutch is lighter to operate than the conventional sprung pressure plate & makes the car more pleasurable to drive. Especially in traffic where the heavy action of the 10" can be a real pain. (in the leg)

 

They both have a superbly progressive action, especially the 10 inch - if you have the leg muscles. I believe the diaphragm spring is gentler on the crankshaft thrust bearing as well as your left leg. Of course, if you follow Bill Heynes' instructions, you will always treat the clutch as a rare luxury to be disengaged infrequently and for the shortest time possible.

 

Thank a bunch. That's what I needed to know.

 

As Peter says if all is correct these cars have a beautiful clutch action. I am most impressed with my 9.5 Diaphragm unit (Genuine Borg & Beck). Just never ride the clutch as they have carbon thrust bearings & ensure correct adjustment. (dependent on slave cylinder fitted). I have gone belt & bracers with mine. The self adjusting slave cylinder & external spring to increase thrust bearing life. The slave cylinder is stainles sleeved as are all brake calipers & master cylinders.