I believe that the HW-16 used grid-block keying, but I'm not sure. The thing to make sure of is that your keying interface can handle whatever the transceiver interface is. The MFJ-452 looks like one unit that will do what you want. According to the manual you can download from their website, the MFJ unit has an interface that handles either positive transistor interface-type keying, as well as negative vacuum tube grid-block keying.
Phil - AD5Xad5x@arrl.netwww.ad5x.com