I'm just a slight motor head, but checking the edelbrock web site shows the following:
PERFORMER (idle-5500 rpm)
PERFORMER RPM (1500-6500 rpm)
If you switch to Vortec heads you are going to have to get new intake to match. I'd stick with the standard Performer if you want more low end.
The 268H lists as "Good street performance with stock converter, choppy idle." That cam is going to have Duration @0.05 of 218 & 218. That is going to push your power sweet spot higher in RPM range (less low end grunt).
For more low end grunt you might look at following cams:
- Dual Energy 255DEH Cam: "Good torque, good mileage. Good RV & towing cam. Smooth idle"
- High Energy/Marine 260H Cam: "Vans, pickups, 4WD & towing, in 350 c.i., good idle, strong mid range torque"
- High Energy 252H Cam: "Strong torque, excellent mileage for 327-400 c.i., has smooth idle, likes high axle ratios"
I made mistake of getting a cam that was too "big" for my 82 4x4 manual tranny truck with 3.08 rear end. No low end grunt. Ended up pulling that cam and putting something close to 252 grind in. Much better.
What tranny and rear end are you planning to run? Is this 2 wheel or 4 wheel drive? What do you want to do with truck?