I bought my 84 cc Eddy heads in 04. Looking to replace the valve springs. Im currently running a 292 purple shaft but that may change. nothing bigger than a 550 lift. Any suggestions? They also need to be the right installed height correct? thanks! its just a regular hyrdaulic cam.

Install the recommended springs the cam calls for , they will have open and seat spring pressure as well as installed height in the spec sheet for them.

I'm going to assume your wanting to do the swap with the heads on the car, correct?
If so Mopar use to sell (maybe they still do scope:) a special tool for doing that.it worked very well, it is a shaft that bolts into the rocker shaft stand bolt holes with slide on part that uses a lever to push the valve retainers down so you can swap the springs.
I'm sure there are cam companies that sell them also: scope:
I bought the BB and SB tools and sold the SB years ago after not racing or working on a SB powered race car.
Their are several things that need to be check on the new springs like proper pressures and coil bind
If it was me and I didn't have a valve spring tester and the other tools to set the springs up properly I would take the heads off and take them to a good machine that could set them up properly for me
No sense in taking chances on having a valve break off the stem due to problems from not making sure every thing is done correct from changing the cam and springs

Wityh the tool you are talking about you have to apply air pressure or stuff something in the cylinder to keep the valve from dropping into the cylinder.

That's true of any type tool you use for head on block, overhead valve spring replacement.

I’d just put another set of Ede springs back on the heads.
They’ve been working fine for 18 years.

No need to reinvent the wheel here.

I just did this last year on a set of 84cc Eddies with the heads still on the car.

This is what I used: https://www.manciniracing.com/ben2pivaspto.html



Used the detachable hose off of my compression tester with the air compressor to pressurize the cylinder. Had to unthread the needle.

The retainers are probably going to stick on a few valves too. The valve will open against the pressure in the cylinder instead of the retainer popping. A small shot of some penetrant on the stem should do it.

That's what I did after several years in service. Running the RB SSH-44 with stamped "HD" rockers from MP. Good running old hot rod.

That's what I use. I've been changing my valve springs every winter the last few winters with my engine in the car. 440 with Trick Flow heads. I put a socket in a heavy plastic bag, put that on the retainer and give the socket a few taps and the lock should come loose from the retainer

I just smack the retainer with a hard plastic mallet. That loosens up the lock.