Hey, I'm looking at an old shamal wheel with a campagnolo hub and a shimano freehub, and I want to put it on my track bike. Can I just pop off the shimano freehub and screw on a cog and lockring, or is there more to it than that?

Thanks.

No.

Yes.

Shimano hubs have a splined interface to the freehub which contains ratchet teeth and pawls. You can remove them and use a Surly Fixxer which interfaces to standard threaded cogs and lock rings.

Campagnolo freehubs have the ratchet teeth in the hub body and pawls on the freehub body so they can't be converted.

Track hubs are a specific hub that is double threaded on the drive side, 1 for the cog and a reverse thread for the lock ring with a narrower axle width of 120mm overall.

It's a nearly impossible task to do well. If you want to do it badly, kludge it together, and make a death trap, then JB weld is your friend.

I've heard of a few people actually brazing the cassette body to the hub, but that's also pretty absurd.

Just build a track wheel,
Campag shamal is a disc time trial wheel, I believe , are you planning track-racing ? on a Velodrome..
pursuits, time trial ?
are you sure its a Shimano freewheel ? Id expect thats Campag too

Pictures?

It's a 40mm deep alloy wheel with 12, 16, or 21 holes and you need to match the original lacing pattern if you change the hub (which people have done).

Campagnolo sells Shimano compatible freehubs for 2007+ over-sized axle hubs and used to do the same for 1999-2006 hubs.