I need schooled on solid roller lifters

Ok I'm pretty much a newbie to engines when it comes to building them. my current engine has a solid roller Ultradyne cam.I dont know much about the parts that are in it.
Now for my ? Are solid roller lifters some what standard. I know that they can be had in different diameters.I am wondering this in case I ever have to replace mine. If you guys gould take the time to give me a little course in solid roller lifters I would really appreciate it. I dont post alot but I lurk Alot! Thanks I may be asking dumb little questions like this from time to time so please be patient.
Bob Siwik

You have a lot of choices when it comes to lifters but most of the good ones have been and will be around a long time. Most likely if you ever have to replace any the big name brands will still be around. What is great about roller lifters is their ability to be rebuilt too. I have reused lifters many times and still have a set from 1992 that I bought off of Tracy Dennis before his business boomed and have ran them in three engines and currently are being "borrowed" by a bracket racing buddy of mine. That may not have answered your question but I'm sure someone else will chime in too.

Factory 460 stuff is readily avalible from companies like Comp Cams, Isky, Crower, ect. They are .874 in diameter.

Well stock lifters were hydraulic flat tappets. Hydraulic lifters have a little bit of cushion or "give" to them which are perfectly fine and all. But with a race engine you don't want any give, you want that valve opening all the way right away. Both are great, solid lifters are used for race and high performance engines. Rollers don't need to be broken in and are COMPLETELY interchangeable with one another. Unlike the flat tappets, they do not require to be worn to the cam and because of that they are able to be used on any lobes and cam any number of times. Any other questions just ask, I know you might have another question I didn't answer. Pretty simple actually. Don't sweat it with the "stupid" questions, we all have to start off somewhere. I just turned 16 and I know a TON, but I still have questions because I don't have as much experience. I've only been doing this for a decade now unlike the rest of the guys on here.