If you do it correctly, you will not at all have to worry about losing timing correlation. What you do is remove the valve cover, remove the chain tensioner, grind off a link of the chain and use a clip type master link to hook the new chain to the old chain. Do this so that the chain will feed down into the engine on the drivers side. Turn the engine with a socket on the crankshaft bolt and feed the new chain through the engine. When the new chain comes all the way around, remove the clip master link and connect both ends of the new chain with a permanent master link.
Then push the plunger through the tensioner then start it back through so that when it gets oil pressure it will ratchet into position.