how slow are you rolling on the throttle?
when you say "roll on" are you saying, twist it fast,,, or twist it slow???
I have the 351 kit stock carb jetted, air box mod top, Q4 pipe and a 15 tooth front sprocket. with that i can lift the front wheel in first and second by twisting the throttle.
Second gear is more dificult and i need to be down in the grunt of the power band but 1st gear is very easy. i dont pull up, i dont lean back,, i just twist. you must be doing something wrong..

 

My 09 with a 13 tooth front, FMF PC4 and a Powerbomb pulls the front easily in 1st with just the throttle, with a little english it will do it in 2nd and 3rd. I weigh 220lbs. Not quiet like some older enduros I've had but it does it. On the stock bike it doesn't get to the torque until the revs are up, my old stuff had tractor like torque just off idle, thats the difference.

 

Really?? Our bikes are modded similarly, and I weight 30 lbs less than you but I could never get it to pull up easily in first with just the throttle. You must have great technique not to have to clutch it up.