All my old gaskets (intake gasket, etc) are stuck really tight, and would only comes off in bits and pieces. Any advice on how to remove it?

 

just get them off any way you can and replace them... its really the best choice, just get a flathead in there and try and pry them up

 

maybe a chisel just don't tap too hard and angle it good maybe.

 

If the gasket is intact you can just leave it alone and reuse it. If not use a brand new razer blade and a small butane torch to remove the old gasket. On aluminum stuff be very careful not to scratch the mating surface.

 

Spray it with gasket remover and then use a gasket scraper. It will take some work.

A wire wheel does the job but you have to be very careful not to damage the flanges.

There are also gasket removing discs available for grinders.