new motor mounts?

[jethrow6978]

hey guys or girls
My 69 firebird ls2/t56 setup vibrates very bad at about 65 and higher. I am using the 327 frame stands and tall and narrow mounts. I also run a BMR crossmember. I took measurements of the trans angle and it is at -6 degrees. and after doing some internet searching i found that this is alittle too much downward angle. I recently installed the heidts four link kit with 9 in housing and coilovers. The car used to never vibrate with the old leaf spring setup and 10 bolt. I measured the pinion angle and it was set at +6 degrees. I know this kit lowered the rear axle in the car roughly 2 inches. After having a new shaft built and rebalancing my wheels and trying to adjust the coilovers up to make the angle alittle less , nothing has changed. It still vibrates very badly. I called Holley and someone told me -6 degrees is way to low and they suggested these mounts. https://www.holley.com/products/ls_p...parts/12618HKR. My question is has anyone used these mounts? pros and cons of each would be greatly appreciated. I wounder if i need to purchase the crossmember to match the mounts also or can i keep my BMR one . The swap parts for this set up just keep increasing in price so any info would be awesome.