Tony, I have dynoed numerous engines with hyd cams where the upward trajectory of the hp curve was still fairly steep....... only to have it fall off a cliff when the lifters gave up.
It usually works out that way when the heads and induction are pretty good and will support more rpm than what I typically can get out if a hyd cam/lifter package.
Sometimes it’s high enough where the owner doesn’t really care...... sometimes it’s not, and then decisions and choices have to be made.

For myself, I really prefer any type of what I would call a “high performance” build to have the valvetrain be suitable for about 62-6500rpm capability, even if the power peaks are lower than that.

Some customers or builds just aren’t a good match for solid lifters....... then the expectations need to be adjusted.

The last hyd cammed BB I dynoed was a 505 with a pretty mild hyd cam(.483 lift), using lobes I have successfully run to about 6300 in oval track SB’s.
This 505 had rpm heads and 1.5 Mancini rockers.
The cam was pretty short duration and coupled with a small intake manifold(original Torker), peaked at a low rpm(5100), which was a few hundred before the airflow numbers started backing up(this is usually the first tell tale of valvetrain instability).
I was making pulls to 5700, and never heard any unhappiness from the motor, but the airflow numbers indicated some loss of control above 5400, and the motor lost 30hp from 5500 to 5700.
Based on past experiences, In the car, I’m sure it would still feel like it was perfectly happy to about 5900-6000.

The rest of the valve train is the same as before. Smith Brothers pushrods, Isky ductile rocker arms gone through and bushed by rocker arms unlimited and Brad Penn 20w-50. I've actually messed with the pre-load a little to see if it made any difference and it did not.

I'll most likely be calling you within the next year or so to have you spec a cam for me. I think I'm just going to go with a solid; the Mopar 528 sounds like it will fit the bill pretty good. This is a FAST type build so; it's weird (HP manifolds, crappy 301 intake and etc.)

If it is true street car that rarely sees the north side of 6000 rpm then there is probably no downside to using a good hyd flat tappet cam. It might give up a little peak power but if your aren't shifting at redline then it doesn't really matter.

That was the conclusion I came to after trying 5 different cams in my Coronet. The hyd flat tappet was quiet and had the same peak power as the solid flat tappet cams. I tested all of those cams on a chassis dyno so I could see what they were doing, but my butt dyno was perfectly happy with the hyd cam too. I was using good rocker arms, good pushrods and good springs so your mileage may vary.

I think whatever Tony does, it should include a before & after chassis dyno session.

Would be pretty cool actually... although I don't think I'll be showing up with five cams like Andy!

I've been running an XE295HL cam in my 440 (w/ OOTB Indy SRs and 1.5 Harland Sharp rockers) for about eight years now with no issues. The valve train/lifters are pretty noisy. Of course, the engine rarely sees anything over 5500 rpm, so take it with a grain of salt.

From what I've heard first hand, that's the XE hydraulic "signature".

From what I remember the Xtreme Chrysler hyd lobes were very quiet. I don't think the Chrysler hyd lobes are offered in any of the catalog cams which might be why they aren't very popular. You have to know they exist in order to buy them. I just used them that one time and they worked great but I haven't used them since. I think that was the last time I used a hyd flat tappet cam.

The XE/HL lobes are the .904 fast rate hyd lobes.
The 275, 285, 295 are all catalog cams.

There have been numerous posts throughout the various forums where owners have discussed/complained about the noisy operation.
Again, this comes right back to the bleed rate of the lifter.
For a “normal” lifter with regular hyd internals, the slower the bleed rate, the quieter it will be in operation.

Tony, I wasn’t really suggesting parts swapping on the chassis dyno....... more like a test it as it is now for a baseline, then again after the upgrades.

I vaguely remember something about the lifters that I installed with the XE295HL cam being somehow different than what is regularly sold with them. I remember Comp selling some "special" type of hydraulic lifters that may have pumped up quickly and essentially acted like solid lifters afterwards. Anyway, my point is that I didn't use what Comp typically suggests for the XE295HL cam and used lifters that (IIRC) a guy at Comp that I talked to suggested instead. Obviously, my memory on the subject isn't too good. Maybe someone with more experience like fast68plymouth knows the type of lifters that I'm referring to.

Okay, looks like I was running a XE285HL cam in my 470 when I did that article but they spread the lobes to 112 which is why I always thought it was a custom cam.

I guess I don't have anything to add on the noise or the issue people have with those cams not pulling RPM well. The setup I had ran past 7000 rpm on the chassis dyno and it was very quiet in the engine. Maybe I just got lucky with my install for some reason.

Maybe the appropriate lifter bleed-down rate and the benefits of those beehive springs really pay off with that style of cam...

I know Dwayne, I was just joking .

My current xe284 (non-hl) cam seems pretty quiet. Maybe because of the less aggressive grind?

The noisy ones I heard were the original like yours, not the HL. Maybe you got lucky and they sent you an old pre-Xtreme grind!

I have the Comp XE295HL in my red 70' Charger with close to 30,000 miles on it now. It is a little noisy but doesn't bother me at all. My car has power disc brakes & I did have to add a vacuum can that I hid under the battery tray. It used to get a little dicey if I got caught in bumper to bumper traffic. Much better now with the can.

The XE/HL lobes make very good power for hyd cams.
The upper rpm power is “usually” limited by the lifters.
I think it’s the exception rather than the norm that a motor combo using one of those cams, along with good heads and exhaust, will peak at the rpm determined by the “combination” rather than the lifters ability to maintain proper control of the valvetrain.
However, I’ll admit I’m basing that off a pretty small sampling of examples when compared to how many are in service.

In the MM article they tried the beehive springs, and on that motor were worth a zero rpm gain.
Interestingly(?), I had been down the fast rate hyd cam road well before that article came out and had already come to the conclusion the issue was the lifters.
A Moparts member was exchanging pm’s with dulcich while that build was going on, prior to the article coming out, and he had been passing along some of the info to me.
When I heard what the cam/rocker plan was, I said it wouldn’t work....... and it didn’t........ at least not well enough for them to reach their goal.
The final test they did provided the “proof” that the lifters were the thing limiting the upper rpm capability........ but it also showed something else, that they never touched on, but if you look at the power curves it’s pretty evident.

If you do a search for something like “noisy comp cams xe cams” you find no shortage of complaints.
I had forgotten about my very first experience with one until reading a few of them.
We rebuilt a 305 sbc for a guys boat, and he wanted just a little more grunt to help get water skiers up.
We put in either an xe250 or 256(can’t remember which), and it worked well enough in that regard, but from about 4000rpm up the valvetrain was horrendously loud.
We went and checked everything over, found no issues...... it was just that noisy.
The noise was unacceptable to the owner, so we ended up installing a stock replacement marine cam in it...... which was way waaaay quieter.

I dug around on my hard drive and found some of the original cam test data. This is from 2004 but I was able to export it to a jpg file so I think I can attach it here. The XE285HL cam curve looks pretty much the same as the curve from the solid lifter cams. I didn't always let off the gas at the same point so the drop off point changes. I think the first test I did I freaked out at 150 mph and lifted but as I got more comfortable on the dyno I held it longer. Some of the last tests I pushed it past 160 mph before lifting.

Here is the same info with RPM as the axis. At 6000 rpm the hyd cam was making the most power. By 6500 rpm it was making the least power so perhaps it started to leak down after 6000 rpm. But even so, it was a strong cam in this engine. Quiet, no maintenance and more power at 6000 rpm seems like a decent combo for a street engine.

here is a link to the article. also if you right click and open the image in a new tab you can see the graph nice and large.
http://www.moparts.org/Tech/Archive/bb/Lobe.html

the baseline is the mopar 528 cam?
that cam looks like it works great in that motor, but the racer brown looks super punchy on the low end, maybe the short duration plus the tighter LSA?