Nope, I have done several Slants, you don't have to change the cam(yet).Just making it breath better with a larger carb and a good exhaust.
I did a test with a 67 Dart 225. Stone stock the thing had a hard time to run 90 mph flat out.It had 2.76 rear gears. With $800 of parts (all new) 390 4 bbl Holley,Clifford intake,Clifford shorty headers,2 1/2'' single exhaust with a good free flowing muffler(I used a Flowmaster 40 at the time)a good tune up with a Petronix electronic ignition and worked distributor advance.The car had no problem pegging the speedometer.With the stock cam/valve springs it was done at 4800 rpm.I switched to 340 Valve springs and the engine would see 5500 rpm. The sky is the limit from there.
