I just got a Chicom Type 56 chest rig (the 3 mag cell version) to run my AR. Before any flaming starts, I think it's going to fit MY needs, i.e. a light weight, low profile, inexpensive rig for  running the range and possibly home defense.
I knew ahead of time that the 4 grenade/cleaning gear pouches were going to be small and of limited use but, holy cow, are they small and of limited use. I've seen vids where guys have replaced the side pockets with molle and added some modern pouches. But, before I go through that trouble I'd like to hear from anyone who kept their rig stock and how/what they put in the small pockets as well as any other mods that may be suggested.

SADF Pattern 83 Chest Rig is moi Bueno:
Attached File

I modified one 10 years ago maybe.

If your wife has a sewing machine, and you have more time than money it could be worth it.

main thing is that ar mags are too short I'm pretty sure.

you could put foam blocks in the bottom of the mag pouches.

then cut off the wood toggles, to replace them, buy a snap / button kit at harbor freight. Black out the snaps.

Then if you want pistol mags on it, cut off the small pouches on one side, get your wife's sewing machine with the thickest needle to can find. Get some 1" strapping, sew every 1.5" with 1" verticals spacing (I believe)

it seems like a lot of work. Maybe buy a surplus FLC from midway, some pouches, and be done?

Once I had a couple:  one dedicated rig for each AK platform.  I got rid of them.  No good way to mount an IFAK, no good way to modify them.  If you were to modify them for molle, the investment in time and money would leave you with a rig still not as good as a purpose built molle/AR rig.

Sad fact is they are not very good compared to what you can get for just a little more $.  Lots of surplus Molle stuff on the market, stuff purpose built for AR mags.  You can get old Blackhawk rifleman vests for $20 with pockets purpose built for AR mags with better retention.  Old milsurp FLCs are like $5.00.  The EE is full of cheap milsurp and high end gear.

I think the Chicom stuff is great if you wanted a cheap AK rig to store away and forget about until FO time.

Run around with it a few times to see if you really want it.  Then try out some other gear.

A little confused by yuour statements as you say its what you need for your needs yet ask for opinions on heavy modifications.

Personally I would ditch it and got to Ebay and pick up a FLC kit or a Ranger Rack kit.  Less then $100 for either and infinitely adjustable to varying needs.

My goal is a lightweight minimalist rig. Three mags (+1 in the rifle), basic blow out gear, maybe a flashlight and a multi tool. That's about it.  I'm not carrying radios, grenades, or IR strobes.
That SADF 83 looks like a nice rig but, I only want one stack of mags on my chest and after 3 pages of Google search the only ones I found were 2-3 times what a I paid for the Chicom.
With a Magpul Ranger Floor Plate installed, the mags come right to the top of the pocket. If I decide I need them a little higher, I can throw a sealed roll of 3" gauze in the bottom of the pocket. Lift & extra med supplies in one.
I don't mind going through the trouble of adding molle webbing to the sides for some more practical pouches. One of the points of my post was to inquire if anyone had good way of running the stock pouches before I removed them and went the molle route.

Yup.

Got one to haul my 74 mags in! Perfect!

You can shove one of the old USGI 1st aid dressings into the side grenade pouches.
Those things are cheap, and just barely acceptable.

As to putting gauze under your AR mags to make them actually graspable, I get a miniature panic attack when I picture being shot, and having to dig out a spare roll of gauze that's under my mags, in that deep narrow pocket. Oh, and the wooden toggles.
Yes, I know dudes did that in Nam to raise up the mags in their pockets.
(Also, as an aside, US field gear in Nam was shamefully, embarrassingly inadequate)
I have a few old chicom rigs and variants for historical interest, but actually using one doesn't seem like a productive use of my time, or even fun.

If you must, sew a PALS grid onto the sides and add a real IFAK.

sic_ness

I couldn't agree more. The gauze at the bottom of the mag pouch with be 2nd or even 3rd string medical, not first line. Someone had suggested foam blocks to lift the mags higher. I thought a sealed roll of gauze would accomplish the same thing while also serving a secondary purpose.
An actual (and accessible ) IFAK is a priority.

I think that the small pockets in their stock form hold items that don't fit your needs (as you said, no radios, no strobes, no cleaning kit in oil bottle form).

BTW...they are not grenade pouches, the rubberized one is a dressing pouch, the one with the sleeve insert is a cleaning items pouch, the others 2 for loose ammo in stripper clips.

Removing the pouches and putting pals webbing is the best solution, or even cutting molle slits with a knife and a hole puncher.

If you somehow want to modify the stock small pouches without removing it you can either use a speedy stitcher and divide the pouch lenghtwise to hold more conveniently multi tool and pistol magazine sized items or sew a large Hook flap on the pouches lids (mated to a large enough portion of loop on the body of the pouch) to make the small pouches securely hold something bigger. These are the mods you are basically stuck to if you don't want to remove the pouches.

You can fit an Israeli dressing in one of the side pouches. Maybe a  compass. Small flashlight. Add some plastic buckles on the back apron strings along what ever you call the other plastic hardware (ladder locks) to keep the straps from flapping everywhere. The wooden toggles that keep the magazine pouches closed are actually better then most people understand. The trick is that if you want to access your mags quickly you only put half the toggle through the loop. Then you can just nudge it with your thumb and it comes undone. If you aren't worried about speed put the toggle all the way through and your pouch won't open accidentally.