Roller cam hands down ,just on the fact it will not fail in the first 20 mins,like a flat tappet cam on break in.Theres no break in on a roller cam to possibly destroy the whle engine.
Anything I ever build is going to have a roller cam from now on,I got lucky on my flat tappet cam soo far,about 1hr + of run time.
Theres just too much worry on a flat tappet on break in.
You can knock about 50 bucks off the price of the roller cam,because you will not need the 50 dollars in special oil to break it in ,like a flat tappet.
2 bottles gm eos 20 bucks and then the oil and filter that gets replaced right away ,meaning you have to replace the oil and filter after break in,might be more than 50 dollars in oil and filters and additives for a flat tappet,plus none of that means theres no chance for it to fail.
I have seen roller cams where the spider broke and the roller was sideways on the cam and had eatin most of the roller away,it was almost square,all that was needed was a new lifter on that same cam ,because a few wear marks are irrelevant on a roller because the is virtually no friction .
Beyond the fact it will not fail on start up,it will produce more power and idle better than a flat tappet.
A flat tappet is taking the rest of the motor out with it when it goes,I have never heard of a roller cam failure ever.........they may fail I just have never heard of it.The roller in my 200000 mile 5.0 motor looked brand new when it was inspected......