I have had a Rippie 15lb. flywheel, (machined down GM stock single mass Camaro unit), for a long time. It has given good service, but rattles badly.
The reason I mention this is that I believe the rattle is not directly proportional to the weight of the flywheel, and getting a slightly heavier flywheel wouldn't necessarily cure it.
Mine rattles up to 2,500 rpm in 1st gear.
Q?- Do these dual disc units hold up to the big inch LT5's? (Not that I have to worry
).