freewheel on peugeot bike
 

http://www.parktool.com/blog/calvins...ng-older-bikes

calvin corner in park tool says following:

"Rear freewheel & cogs- freewheel bearing surfaces are worn and will make some rumbling noises when coasting, so don't coast. Cogs are worn and once they begin skipping, a new hub/cassette will be needed. You will never find this, so expect to purchase a complete wheel as well as a cassette."

So I worried about the condition of this freewheel. If in near future I have to replace it, can I use a new wheel with suntour hub and shimano freewheel to replace it? thanks

The malliard helomatic hub/freewheel was a proprietary system that has long since been discontinued, spares would be difficult to find except possibly on e-bay or by purchasing an entire old bike for spares. It will work fine to replace the hub & freewheel with a normal threaded hub/freewheel or go to a casette and freehub (8-speed upward would need the frames rear triangle spread to 130mm).

Hmmm........That looks like a Campy Equipped Peugeot from the mid 80's (A Victory?). Specially as I seem to see a Campy style skewer adjuster there with a chromed head and wire loop. So we're not dealing with Heliconatic hubs if that is the case. You will need to refer to Campagnolo hub maintenace procedures then which I suspect is not as unusual as the parts coming from a Helicomatic.
The hub on the other hand could still be French Maillard (700 model, most likely) but with most likely, English Tthreading. Maillard FWs are pretty rugged and could survive many years without internal overhauls and just flushing/cleaning and repacking with grease. Some people just go ahead and replace the whole block completely with new cogs too if internal things like the pawls and springs wer out, as NOS Maillard FWs with cogs are still very affordable.
Chombi

There is no need to replace the complete wheel when you replace a Helicomatic hub ( unless you like mismatched rims).
I recommend you stick with a new hyper glide 5/6 speed hub, and avoid the pain associated with cold setting the frame and altering chain lines.

I'm suspecting that the QR skewer is not original. The derailleur is Victory, but the skewer is Record.

Are there any labels or identifying marks on the hub shell? If not, remove the wheel from the bike and take a close-up picture of where the axle comes through the freewheel body. A Helicomatic hub will have a splined aluminum retaining ring whereas a freewheel will have a splined or slotted tool interface on the steel body of the freewheel itself.