What is the projected life of a solid roller on the street? ...
This comes up a lot. The answer depends upon where you ask the question. I look to a bigger brain trust with Speedtalk. Here's a link to this question: https://www.speed-talk.com/forum/viewtopic.php?t=43176
If you search the site, you'll see it's not the first time the questions has been asked and bench raced. In that particular thread, there is a response from CamKing. He is a cam grinder and designs custom pieces for many of the NASCAR and other race series teams. But with anything, it always depends on how the particulars stack up for you. Maintenance is very important and has a lot to do with valvetrain life when working with a solid roller.
I'll give you my experience, 2002-2005 in Las Vegas. Got tied up with the guys who couldn't keep a Rat chevy together, kept eating solids and taking out crank and rods. Usually around 1500 miles, sometimes up to 3500. I did not build the solid roller motors but inherited them and fixed them. Most were mellow lobes high 290 adv, 240-250 @ .050. At the time lifters were either bushed or needles and not oiled pin. Not racers, streeters, and probably did not take care with lash settings but also didn't run them for long.
When I called Comp to ask they said "not for street. rebuild solid roller lifters every 75 passes" 75 runs X 1/4 mile...no kidding, their words not mine (again 2002-2005 not now)
So, we add modern oiled bushed pins, we add tight lash to stop hammering, cam profiles get better, and more than anything, we aren't talking a Rat that seems to side load a lifter unnaturally. It should be better, and some guys run the heck out of them for years, but some don't
My issue is, I had to repair someone's carnage so many times, and we fixed them with hyd flat or solid flat and everyone was tickled pink, chosen depending on RPM, and they just lasted.
So if we start at 75 1/4 mile passes or even use 3500 miles that I saw on these builds, I have a hard time believing in a solid roller on the street for anything more than a race wolf in sheep's clothing, and with that comes risk. If it's 10 times better with a tight lash, oiled pin, you are at 35000 miles, but no warning with a solid roller, when it breaks, it breaks good.
Nowadays, for 6500 peak or under, I'd do hyd roller. My customers aren't racers, but for those that want more RPM and reliability, I'd do a modern tool steel or DLC coated solid flat tappet. Racing, you generally need to run a solid roller for the profile, so I get it.
I do know there will be 50 guys that say they last, and stuff has changed, but I am not a fan for a street strip vehicle.