Diagnosing a clutch issue

[decrobinson1999]

Hi,

I have recently fitted an aftermarket clutch pedal which works really well, the old one was sticky and didnt feel right, however in the past few days I have been experiencing a few issues, mainly with the clutch feeling like it isnt engaging properly, like its slipping.

After a period of time when driving the car hard the revs rise considerably quicker than my speed when I put my foot to the floor and then will drop back again and begin adding power, it feels like the clutch is slipping (from what I know) however I was unsure if it could be due to not having braided stainless clutch lines meaning I am running into problems with the master cylinder not actually engaging the clutch properly in the first place and giving the sensation that it is slipping as it doesn't seem to be happening all the time like I'd imagine a slipping clutch would.

Thanks for any advice in advance