Valve lift up to about 0.530 inch is fine with the stock rocker arms, but will usually require better valve springs and stiffer push rods.
The need for a looser converter is a function of power band, overlap, and compression. If the power band is low enough to provide good vacuum at idle, and if the idle quality is good, the stock converter should be fine. 2V heads have much more leeway than 4V heads in terms of power band. Cleveland heads do not need lots of overlap to make power due to the shallow combustion chamber design, don't select a narrow LSA cam on the assumption it will make more power. It will reduce low rpm torque which is opposite of what you want to do using the stock converter. Raising the compression improves low rpm torque and thus helps in regards to using the stock converter.
600 carb, cam, & headers are fine, but the biggest improvement in performance comes from compression and gears. Your friend can install the carb, cam, and headers and end up with a slug. Failure to raise the compression will yield less than satisfying results. Of course raising the compression will require a carb with richer "street performance" calibration. I'd suggest three phases. Compression, carb & ignition in the first phase.
By compression I mean around 10.2:1 mechanical compression, or 7.8:1 dynamic compression. The inexpensive way to do this, assuming the block & heads have never been milled, is Fel Pro 8347 head gasket, Sealed Power L2348F pop-up dome pistons (formerly TRW), and milling the heads 0.030 inch. The amount the heads are milled fine tunes the dynamic compression based on whether or not the block & heads have been milled in the past and/or based upon the seated closing of the intake valve. 10.2:1 mechanical compression can also be achieved without having to mill the heads by using a custom ordered set of Ross pop-up dome pistons.
Add headers & 3.50 gears for the second phase. After going this far the car will have tremendous "pep", your friend may decide the engine doesn't need a cam. But if they still want to put "a cam" in it, do the cam last and choose cautiously.
By the way, if the stock 2V cam is worn badly, reproductions are available from Sealed Power.
