want more power from my 318...

I would tune it the best you can before buying a new cam.
You said you think you have a exhaust lobe gone on the cam????
What makes you think that???
The pitcher of the motor is of cylinder #2 and the adjustible rocker that someone installed.
This is likely due to a stamped rocker breaking and being replaced with an adjustible rocker, because thats all they had.
That adjustible rocker is on cylinder #2's exsaust valve.
It's most likely not tight enough to open the exsaust valve all the way makeing the motor skip and run like a bag of rocks.
I would get all your rockers on correctly and do a compresion test.
If it checks out, i would run the motor the way it is to see if you have any other problems first.It might have a good cam in it already and run like a bear. GOOD LUCK:burnout:

P.S. GET A BOOK ON BUILDING SMALL BLOCK MOPARS AND A CHILTONS MANUAL ON YOUR YEAR CAR.