Crane or Competition Cams are recommended in the stang magazines for the roller conversion cams. You should not have much of a problem finding what you need since you are running mild heads. I think the important thing in matching your cam to your engine is to match the flow rate of the runners in your heads. No sense have a high lift, long duration cam if your heads cannot move all the air which the cam allows your engine to suck in. Remember, for low end torque, it is air VELOCITY which does the job, not how much air moves through the heads so much as how fast it moves. That is why the 351C 2v heads are generally recommended above the 351C 4v heads. The dinner plate sized intake valves in the latter don't really help where most street cars live - low to mid-range rpm. The extreme energy series of cams are nice, but I don't know whether they have a roller conversion in that model of cam. You could call the 800 number for either Crane or Competition Cams and the tech person/sales person will have a recommendation for you. Shouldn't be too difficult to find what you are looking for. BTW, I was reading a dyno comparison between a roller and non-roller application of the same cam in the same engine and there was no reported difference in hp or torque, maybe 1 hp and 5 ft lbs, nothing you would feel or see on the street. I think the advantage of the roller is simply maintenance - longevity. Also, with the roller cam there is no break-in period required for the cam. If you are running aggressively modified heads, something towards the radical side, the roller cam can have a more aggressive grind, steeper ramp up, which helps performance. The key is matching all your components to eachother. Synergy gets the job done. good luck.
sure it's fun (most of the time), but it's only a car.