Will Bog Wood Drop Ph?

Will bog wood drop my ph I have just got 2 peices of it as I am getting electric blue rams and want my ph in the low 6's. my ph was 7.6 before I put them in when should I check if it has dropped or will it drop at all?

It may do, some pieces do and some don't. You will just have to monitor it to see what happens.
 
Be aware the the pH drop won't last forever though, the pH will slowly increase with water changes and other things.

How are you suppst to keep fish that like acidic water when every time you do a water change its gonna go back to the High 7's

Bogwood does work but it takes about 2 months to lower the pH 0.1-0.2 per piece.  Generally, I have found 10LB will reduce 0.2 but it takes a long time.  I do not have issues with it 'going away' like some one else posted but the issue I have is it is not instant by any means. 
 
To lower your pH try getting some RO water and use that with your normal water changes.  Maybe every other water change use RO Water.  You will find RO water is 7.0 pH and your tap is lets say 8.0.  If you do 50% RO 50% Tap you will have 7.5 which is a good start. 
 
If you have any questions just let me know.

I was going to get a buffer or something like that but everyone says dont use chemicals, what's is RO

RO is reverse osmosis; it's water that has, literally, had everything removed from it, so it's completely pure. (If you hover your mouse over underlined abbreviations on this forum, it'll give you a tiny pop up with the meaning )

You will need to mix it with either some tap water or remineralising powder, as it is too pure for fish on it's own.