While I can not say anything negative about those Holley heads, I will say you made an excellent choice over the E-streets. Not to hijack your thread or anything, here is my results from those heads, particularly with the valvetrain.
WARNING: Edelbrock E-Street Heads - Ford Mustang Forums : Corral.net Mustang Forum The casting of the E-streets are a bit rough; but the flow numbers are comparable with AFR 165's, TW 170cc, etc.
As for which cam would suit you best, I personally would not run the TFS-1 cam. I ran it in my 302(now in my 331) and it was one lazy cam down low. It sounded nice, but anything below 2500rpm and the car was a bit weak. Luckily I had 4.10's to remedy that a bit. But one cam I really like is the Comp XE264HR. Great cam! It is slightly milder than the 270HR, but helps keep torque down low. It is fairly tame and worked well the the computer. One thing to note was the torque peak. With the E-streets and Comp cam, my 306 made peak 322rwtrq@3800rpm. For comparison, my other 95(AODE though) with TW heads and TFS-1 cam made 311rwtrq@4000rpm. Both set-ups made peak power at 5300rpm. The one thing the TFS-1 cam has going for it is price. But I would personally look at a Comp Cam or Lunati over the TFS-1. It's not a bad cam; there are just better ones out there. I do have a Comp XE270HR cam if you want it. I bought it from a guy in July to run in my 306(but went with the 264hr). He put about 5,000 miles on it before upgrading-he liked it though $130 shipped!
Rockers: 1.6 Harland Sharp or Scorpion. Stay away from the el-cheapo Proforms. They are small, noisy and cheaply made.
Like everyone has said, it would be wise to check for pushrod length. Chances are, the rods will be a 6.27(unless you have the TF heads or one with the canted valves, which the Holley's might be).
Again sorry to rant!