[DavidNJ]

Agree with Tom, disagree with Excaliber. Roller cams let you have more aggressive ramps. For street cars, they allow a bigger performance/economy/emissions profile under the curve. So for the same performance, you could have a smoother more efficient engine. Or more power with the same emissions and economy.

I believe all current pushrod engines use roller cams. So they can meet the manufacturer's 100+k mile emissions warranty issues. They needed to get that way, the manufacturer's have governement dictated emissions and fuel economy requirements.

For your SBF, the drop ins would have a link bar to maintain the roller alignment. Production cars mount the lifter in dogleg tube that prevents rotation. Another option is to add a key, a little alignment bar, to block and use it with lifters that align against the key. This adds less mass to the lifter.

Hydraulic rollers run to over 7000rpm in the LS7. However, like any roller, the are challenged by mass, ramp, and spring stiffness. To get that performance GM uses featherweight valves, light die cast rockers, light beehive springs, etc.

Figure out your objectives and then order the best cam to meet it. Changing a flat tappet cam to roller cam with the same ramp is useless.

P.S.
In both roller and non-roller cams, solid lifters will allow bigger valves, higher revs, and more aggressive ramps. To get this they need stiffer springs and a stronger valvetrain (rockers, pushrods, etc.). They get the advantage because of the pressure limitations of hydraulic lifters.