Changing 6 spark plugs out of 8?

 The weather is getting better and look forward to enjoying the car.  I would like to change my plugs but there is no way in hell I can get to the 2 front plugs on passenger side the AC compressor covers it. The plugs in there now are AC Delco FR3 cls the owner's manual calls for AC Delco FR5 ls. Is the 3 the heat range rating?  Is it lower or higher than the 5 rating?  If I change the plugs I can get too and do not change the front 2 what impact would this have on engine? I would have the two front plugs changed at the end of the season by my mechanic or just have them all done at end of season.  Car runs good.     Thanks for any information.

You can get to them through the wheel well with an extension and a flex joint.  I would change all eight spark plugs without question.

I agree...change all 8.

Thanks for the info I ordered a flex ratchet will try.

Changing spark plugs is part of learning how to take care of your car properly.   Installing your new plugs is easier if you'll slide a piece of 3/8" fuel hose over the insulator.   A piece about 8" long works good, and will also help to prevent cross-threading the plugs!