I usually have a 16x texturepack, and edit the blocks to make them 1x1 or 4x4. Just cause I don't mind how they look, I'm more interested in the fps.
Does having only my blocks 1x1 and rest 16x help my fps? or is having the blocks 16x too cause no difference?
In general, yes. What's happening is that by having smaller textures the game needs to hold less information in memory. With less to process, this frees up both RAM and processor for other things. Generally, this will lead to slightly better performance.
Keep in mind this isn't the be-all end-all of boosts. Most of what bogs down Minecraft isn't the textures, but what's actually happening in the world. Entities, redstone, chunk loading, all of these and a bunch more will generally be bigger performance killers than your texture pack. As such, even with a pure 1x resource pack the improvement will probably be pretty minimal.
There's also the issue of your own system. If someone's running a total craptop then they probably need all the help they can get. In this case, turning features off in Optifine and using a lower-resolution pack can make the game a lot more playable than it would normally be. Inversely someone that's running a half decent gaming PC won't likely notice a difference. Yes your FPS number might be marginally higher, but the difference likely won't be visible and there will still be hitches in the framerate when viewing things like large quantities of mobs.
I suppose the long and short is that if you don't mind low-res textures and really NEED to eek out those extra frames for playability reasons then GO FOR IT! But if you're running good hardware then maybe it's better to indulge and get something that's a little prettier instead.