exhaust choices

[SOON2BLAZE]

I used the search function and came up empty, but I know this has been covered. I have a stock 454 and stock exhaust mainifolds in the 2wd blazer. Not much room to work with, but want to hook up something like 2 flowmaster 50 series. For more power should I:
1. H pipe, if so how far back is ideal?
2. X pipe, if so how far back is ideal?
3. 2 2 1/4" into 1, 3" out
4. just run a good old dual set up with 3"

any help would be appreciated. thanks