Should I replace the cam when I do rocker arms, push rods and lifters?
 

Like the title says, I was wondering if I need to replace my cam when I do my rocker arms and pushrods and lifters. The reason i’m asking is because i’ve heard of new lifters destroying the cam lobes and flattening them out, but I don’t know how true that is, and I don’t know why that would happen if you used the right lifters.

Anyway, i’m getting a rattle from the top end, and it sounds like a rocker or a lifter is rattling around, and it’s coming from around the first cylinder. I’m just going to replace everything on the top end, but i’m not sure if new lifters will destroy the old cam

Why don't you see what the issue is first. Maybe you have a flat cam lobe and question should be reversed.

Although I guess the answer to both would be "yes".

"Why don't you see what the issue is first"

Throwing a bunch of new made in China parts at it is not going to necessarily make thing better if stuff in there doesn't need replacing.
Diagnosis !!!

Sputtering???
 

You fix that sputtering problem yet?

Nope, not yet. Although i’m working on narrowing it down.

Reason i’m asking this question is because I want to do a sort of top end rebuild, but I need to fix the sputtering issue first

If you need to do this - why not upgrade?

Harland Sharp Roller Rockers on a Jeep 4.0

I’ve thought about doing those, and they seem to help with how the power is distributed throughout the power band.

Would I need different sized pushrods as well?

stock push-rods
 

They are designed to work with the stock push-rods - they only change the pivot point a little (adds the additional depth & duration)

Sounds good.

I also found a thread saying that an old cam with new lifters in fine, as long as one hasn’t scored the cam lobes. However, it’s the new cam with old lifters that’s going to cause problems.

With that being said, what is the advantage of these higher duration rockers? It says it carries out the power to where the auto trans shifts at, but I don’t have an automatic. I shift around 2.2k to 2.5k, so would I see any improvement on the lower end or around that range?

OK, Hydraulic lifters work until they don't or "collapse" - there's no other reason to replace them except that they are old (judgment call) or if they are scored.
The roller rockers offer reduced friction and a small increase in performance that will be noticeable between 3 &4k - when you're winding the engine for acceleration - in normal, low speed shifting, you probably will not notice much improvement'
These rockers, with a larger throttle body, a banks header, better fuel injectors and a K&N intake system are the componence of a modest 10 - 12 hp improvement. Expensive stroker engines or Edelbrock's freer flowing aluminum head will get you more power at a huge premium

Im familiar with hydraulic lifters, and the reason I want to replace them along with the rockers and pushrods is because there’s no history of anything being done to this, aside from a supposed head gasket job at an unknown mileage. I have absolutely no idea how old some of the stuff on my Jeep is, and replacing the lifters on the 2.5 can be done with the head on the vehicle, and you can grab them with a magnet. Not a very hard job at all.

But as far as those roller rockers go, I don’t think thats what I’m looking for right now. I do want to get more power out of my 2.5, but it’s really not worth it right now. She’s got 290k on her now, and I don’t want to make matters worse by forcing it to make more power when she’s already kind of tired.

I think what I would end up doing is putting in a 2.5 stroker and using those roller rockers with a more aggressive cam and maybe a ported aluminum head.

Yes, it's amassing what low tec inexpensive stamped steel rockers can do. Food for thought in the dyno testing - pretty much what we suspected:

I wasn’t exactly expecting those roller rockers to make such a difference.

However, it was done on a stroker 4.0, and I don’t expect those to make a huge difference on my little 4 pot. Maybe one day i’ll see what difference it’ll make on a 2.5 stroker