King Cobra is a good clutch, and would be just as good as a factory clutch. there are lots of reasons why your pedal is heavy.
it could be
1. Heavy pressure plate already installed
2. worn clutch cable
3. worn/no grease on the input bearing retainer
as for difficult to get into gear it could be
1. no lube on input shaft/clutch disc binding on input shaft
2. low oil in trans
3. loose bellhousing bolts
4. bent shift forks
likely your problems will be fixed with a clutch or clutch cable.