I run a solid flat tappet speced by Dwayne Porter. One of the reasons I did not go roller is because I put alot of miles on my 63 and to run a roller correctly it will need alot of spring pressure as required. Rollers need the high spring pressure for a few reasons but one reason is they dont want any lifter floating (bouncing) as they can cause a roller lifter to get damaged and if the roller lifter goes it is usually major eng problems. Many new cars run rollers sure but they are not set up to be raced at 6000 rpm as they can get away with a bit less spring pressure then the roller racing cams. So I was recomended to replace my roller lifters every 3000 miles if I drive my car alot of street miles just for insurance that a roller lifter cant lose a roller pin or break any other way.
I do know alot of guys do run rollers on the street but since I drive mine alot I did not want to worry about breaking a lifter so I went with this solid flat tappet that is: 264 and 270 @ .050 with .630 and .628 lift with my 1.6 rockers. It is on a 110 LSA and I installed it at 106 ICL. I myself love it as it has a nice tuff rump rump to the idle but is smooth enough to drive it all the time. Just the way I like it. My 63 goes 3700 lbs and ran 11.04 on the only good pass I have on it. But I know it should go well into the 10's as it was breaking up that run from being to lean.
Thats just something to thing about and good luck which ever you choose. Ron