get a mechanic's stethescope to pinpoint the area. i've never worked on a 428, but can't you just use an open end wrench to tighten the bolt? you can try using extensions, u-joints or a crow's foot to get to the bolt also. there has to be a way without resorting to lifting the motor.
Rubelle
65 2+2, 289 (early A code), c/r toploader, magna suspension, centerline convo pros
Rubelle
65 2+2, 289 (early A code), c/r toploader, magna suspension, centerline convo pros