These billet aluminum cab mounts are a factory replacement for your 1963-66 Chevy C/10. The mounts are machined from T6061 aluminum and feature stainless steel hardware. The aluminum mount sits directly on top of the frame just as the original mount. One oversized washer sits on top of the aluminum mount and will keep the body from digging into the aluminum. One large 1/4” thick washer goes onto the bolt and passed up through the frame bracket. There are no other lower parts to these mounts. PLEASE MAKE SURE THAT YOU USE PLENTY OF ANTISEEZE!! If you do not, the stainless bolt will seize on the nut and you will have to cut the bolt off!
Disclaimer: These cab mounts will solid mount the cab to the chassis. If you do not box or reinforce your chassis there could be long term damage to the cab mount supports. That being said, confirm that your cab floor, cab support rails, and inner rockers are solid before installation. Rest assured that if you have a boxed frame or aftermarket frame with a good cab, there is no danger. We have had these cab mounts installed in our truck for 6 years of racing now with no issue. There is also no noticeable increase to NVH with these cab mounts. Only if you have solid engine mounts or something contacting the frame will the resonance transmit into the cab.