Im trying to renew the coolant in my '92 Vii but i can only seem to get half of it to drain out through the stop cock on the radiator. Are there any other drain plugs in the block i need to loosen?

Nope.

Make sure to remove the radiator cap (I'm sure you've done this). You can remove the lower radiator hose, too.

Did all that, but can still only get half the amount out (7qts), then get same amount back in?!?!

"I'm no mechanic but I play one on the internet."

Buy a bottle of radiator flush (not the repair stuff .. just the Gum Out Flush stuff) and follow their instructions on FLUSHING the system. You'll be told to add while draining to flush the system.

Im trying to renew the coolant in my '92 Vii but i can only seem to get half of it to drain out through the stop cock on the radiator. Are there any other drain plugs in the block i need to loosen?

Yes, there is a drain plug on each side of the engine. They can be removed with a hex head wrench, but can be tough to get out if they have never been out before. Remove them only when engine has cooled down. This is a pita job but it will remove all coolant.
You can achieve almost the same results using a cleaner/flush. Follow the directions on the product. For the final flush, have the engine running and the radiator drain open. Keep topping off the radiator until water comes out clean. After cool down, pull the lower radiator hose off the radiator and let it drain. Then replace the hose, close the drain cock and refill with 7 quarts of antifreeze (check manual as you will want 50 mixture and I believe your capacity is 14 quarts). Top off with distilled water, if needed. Now you are good to go for a couple of years.
Getting back to draining the engine block, the advantage of doing so is that your mixture will be 50% distilled water which has no corrosive causing minerals in it.

Thanks guys, ill try that