I think you're on the right track with all the bolt ons. But I think you will need head work as well. 25thMustang is right tho....HP is everything. His car is running mid 12's on a GT40 motor. Most guys making 400-500RWHP can only get into mid 12's because they can't hook up or drive. Brian's car does both.
GT40 combo? Someone put heads on my car?

E7s all the way on my car.
My brother has a set of GT40Ps on his stock bottom end car. His have a valve job, angle mill, 1.84/1.54 valves and matching springs to his cam. With rockers, custom cam, untouched Cobra intake (off a 93 Cobra even), TB, MAF, 24 lbers, LTs, Xpipe mufflers, 4.10s and a stock T5 it has been 11.86 @ 113+. It made 313 at the tires I believe.
With the stock cam it made just shy of 300, I want to say 298 or so. Went 12.11 @ 111+ in that configuration. Might have had an 11.9x, but the cam change happened before the 11s.
His GT40Ps had a bit of money into them, which if your not hell bent on track numbers out of those heads, I would say step up to a better head to start with. We run crappy heads (I run E7s at mid 12s, brother runs GT40Ps at high 11s, father runs AFR185s at high 9s) at this point to basically say, we did it. We are leaving timeslip on the table, but have fun trying to go faster with weak, crappy parts. If this isn't your mentality, it might be best to either bolt on the $300-400 GT40s and stick with them that way, or spend the extra for a good aluminum head.
My honest opinion, as most wont put the time into getting a GT40 or E7 combo to work right.