The STOCK 273 Flywheel from my 65 273 weighed 19 lbs 7.6 oz... I replaced the 273's 9.5 assembly with a factory 340 10.5 clutch/flywheel/bell housing assembly!
And the 10.5 340 flywheel weighed 30lb 3oz... And that's why I previously said I loved the way it now launches!!!
Also I use a Borg & Beck Pressure Plate & and my bullet proof SS Z-Bar (I use to break those early a-body z-bars)
Just for chuckles.. The 273 Bell housing was 28 lbs 8.6 oz...
And the 340's Bell housing was 12 lbs 2.4 oz
So I even saved about 5 lbs... Just saying :cheers: