Are 3speed flywheels and 4speed flywheels the same?

[Rob H.]

Should be the same, I just swapped the 3 speed in my 72 for a 4 speed out of my 70 burb parts truck. The 72 has a 307 the 70 had a 402 originally, Flywheel looked to be the same. I bolted the 12 inch clutch from the burb straight to the flywheel on the 307. Good luck with it, I had to make the rear driveshaft section to get the right length. 3 speed has a slip yoke, 4 speed has a fixed yoke.