depends on whose springer it is, but generally there are no conversion kits. I have a jammer narrow springer on the cb550 and it has a threaded bung on the inside leg. I have seen clamp mounts in the past and all I can say about those is I don't see why they wouldn't work but you better make sure your hardware is up to snuff. Some springer legs (espically on the narrow ones) are oval or flat so I don't know where you would get a clamp to fit - it is probably better to have a machinist make you one so you get a perfect fit.
Is your springer a dampened springer or does it just have a bunch of springs and that is it? mine has no shock and one thing I have noticed is that any brake more powerful than the mini drum tends to cause the front wheel to skip along the pavement under braking on uneven surfaces. Also there is a lot of flex that get introduced with a real brake on a long thin narrow springer.
do you have a pic of the springer? if it is the one in the pic you have it looks like you have a girder front end.
