i have a '97 blazer lt and i just purchased a pioneer deh-p6500 deck to install --is this going to fit in my dash?

It should unless it's a big sucker. Just get a dash kit for it.

It should, i just bought my 97 blazer and my pioneer 8600, and mine fit ok. It was a little snug, and you have to tuck some wires down in there, but it fit.