I know I might catch a bunch of "Newbie" flak for this, but I wanted to brain storm with those who have been there and done that!

I have a '67 vert with:

very fresh 326 3K miles on it.
edelbrock performer intake (supposed to be like stock)
Edelbrock performer 600 cfm carb (tuned pretty good)
stock 140 heads
4speed (I would not think it's 1st gear,runs out quickly)
3.23 gears with posi
260H comp cam

Now I know the 326 is no barn burner, but it should be able to make somewhat respectable power. What is a good head for this motor for more torque, low end power?

My buddy runs a 350 with a 280H cam and 1.65 rockers. His heads are #16's with a 4 speed and 3.23's, and he can flat out rip with his combo.

Is my cam killing me, is it my stock heads, or my lowly 326?

I've tried to see what heads are out there, but I know that they try to match up to the motor and cam, and cannot decide whats good, if you can recommend a head, could you detail why? Sure would like to learn about the reasoning too.

Valve size versus, cc or cr. I'm also trying to understand why my cam would be iffy if his 280H is more extreme but runs real well.

Thanks to any and all that can shed some light. Heck I'll take article links or what have you.