Will they work in a street 440 motor?

Just make sure that you use enough but not too much spring and that your rockers are in good shape.

The "rule of thumb" on stock rockers is they are good for .5" lift or a bit more. The XE 284 is right at this limit so probably/may be OK. If its a slow turning stroker with just right springs OK. If its a fast spinning SB with heavy springs ??.

My son is using the stock rockers in his 451 stroker. XE284 cam, and running Stealth aluminum
heads so the springs are decent for that cam.
Wouldn't want to go any higher than the Stealth/Eddy specs....Just asking for trouble.
As it is, we've been keeping a good eye and ear on the kids set up. So far so good....6300 RPM max and 11.7's thru the pipes in a 3700# Chally and it survives!

I have the source heads w/ stock springs and run the lunati voodoo 60303 cam with stock rockers just fine.

Stock rockers sure are durable when used in the correct application. The magazines doing 350 chevy motors over the last 30 years almost always use some nice roller tipped rocker arms for even low performance builds. Its nice to be able to re use the stamped stockers (assuming they are sound). The money not spend on new rocker arms (and additional QUALITY adjusters) and appropriate pushrods can go to some other area.

If it has a "small basecircle" ground into the cam the rockers can sound noisey when the valve is closed. Same with if the heads are shaved/milled.

I ran stock rockers on a MP 284/484 cam for years. It had the 933 MP valvesprings which have some pretty good tension. Something like 110 closed, around 300 open.

Blew two rockers one night out racing. One pushrod went through the rocker tip. Another broke the rocker in half at the fulcrum. I got lucky, no oil pressure loss, lifters stayed in the bores and the pushrods jumped up into the valley area and didn't drop down into the crankcase and get clipped by the counterweights or rods.

I'd keep an eye on them.

I have been running a XE294H with matching 925-16 springs with stock rockers in my 440 Sixpack Charger with no issues.

Also I'm running the late 70's 440 rocker arms which some say to be equivalent to the mopar hd rockers, ie better than the 60's pieces.

Well i sent the heads out to have the springs checked. I'll be using new TRW stock style rockers and shafts.

Stock springs will likely not have enough travel to prevent coil bind. You need at the very least .060 more spring travel from installed height than the maximum lift of the valve, preferably more. Make sure also to have at leas this much clearance between the valve guide/seal and the valve spring retainer. coil bind/retainer interference isnt fun or cheap. do it right the first time. Once again the partial results of coil bind: