I put bolts through the halves like the ones you got, but I put locking nuts on them, you can see the engine flex in this photo but the mount did NOT break, but I really should put a solid mount on the driver side. The Hilborn Stacks REALLY make it obvious LOL

Charger55.jpg
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