From a bad experience with out of balance driveshafts, the only company that can spin a shaft at the desired rpm is Mark Williams, as one example of my getting the SHAFT LOL, my Strange engineering shaft was only spun up to 500 rpm , thats as fast as they can spin them, after LOTS of wasted money I call MW & they solved my vibration problems & tailshaft bushing problems

1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392 Stock 11.79 @ 114.5