have your parts house cut a piece of vacuum line of the right dia (7/16 iirc but don't quote me), just long enough to slide on the end of the pushrod into the groove on the end like in the pushrod in the pic. The tailor made ones have a thin/shallow groove lengthwise along the neoprene piece which might be to let the air out as it is installed into the tapered blind hole or it might be nothing & just from how it was held when it was mfr'd. Lube it, as it is a tight fit.