You have a CTO model that does not come with specs to look up since it could have several different hardware configs.
HP does not give dimensions for the insides of the case either.
Those links you gave to the Nvidia website only show basic specs for the series. YOU need to decide what card from what manufacturer you are going to buy and get the dimensions from their website. Then measure the clearance inside the case itself. Most likely, it will all work out.
But I don't know which power supply you have either. You need to find out if your new card will need a 6 or 8 pin power connector. Then see if your power supply also has the same connector.
If it does not, you will have to upgrade that also, so I would go with a 600w PSU or better.