Like most other old car people, I have problems with fuel vaporization in the carburetor after engine shutdown. After several hours my 69 GTX 440 usually needs at least 20 seconds of grinding before she'll fire back up. I see that manifold silencer kits are now being remanufactured. These were supposedly installed at the factory on at least the big blocks. Are these worth the trouble putting back on the car? I'm at 6,000 feet here near Denver, although the fuel is supposedly tailored for this elevation. I have as thick a carb spacer as I have room for with the hood insulation pad (which undoubtedly helps trap heat). I'd prefer not to change out my original Carter AVS. The fuel pump seems to put up adequate pressure. Anyone have any experience with or without these pads? Thanks