I call them block insulators and they are the same on all LA blocks, I believe 72' and down, then they used the roll mounts (different "K" member W/loops). It's the mount to block tabs that are different on the applications 273-318 or 340-360. I would not use a solid mount on a street motor. I had issues with breaking mounts (drivers side) in my 72' Van with a 340. I installed a chain at the mount to engine and the corrected the problem. I believe a solid mount would be hard on the motor, the frame and my body. On my van, I was able to tweak the tabs (318) to accommodate the 340, but they are longer on the van than the cars, so it was easy to adjust.