Need Input on Freestyle Technique

I have always used a 6-beat flutter kick when swimming freestyle - nothing else feels "natural." I have noticed that when I do sets of 100s, my times are actually faster when I do then with a pull buoy than when I swim - by about 5 secs. - and I can maintain the same time for 6-8 100s. It would appear my kick is actually slowing me down and I don't know what to do to fix it. I was a fairly good swimming 25 years ago and coaches back then told me my technique was great. Even now the non-competitive lap swimmers who watch me swim also comment how nice and smooth and rhythmic my stroke looks and "sounds" lap after lap. (My point is I'm not "thrashing around the pool" or making beginner swimmer's errors). Also, no one I swim with competes and I don't belong to a swim club, so no coach to consult. Here's what I'm thinking: When I use a pull buoy, my hips are higher causing less drag. I'm thinking that I need to keep my nose pointed straight down to raise my hips. All suggestions/advice/drills are welcome! Please help.