With virtually no experience, I am playing the tunner game with the rest of you. I do understand that the basic manuever is to get more air so that more fuel can be mixed for a bigger bang. I have read quite a bit about the most basic mod. in this area as "hacking" the MAF. I thought mine had been done on my 4g61(at least I paid for it). 
However, since I am putting in 4g63 bolt on's, I got a 63MAF. I had seen many pictures, and read about hacking the MAF. So when I actually took the MAF off myself, I was surprised to see that they are different. The 61 has two cylinders completely separated over a rectangular bottom. On the 63, the rectangular bottom appears to be a little larger, and above it is an ovalized structure like a race track with two curved ends and parallel straights. Just like the pictures. So, I assume that all those illustrations were of 63MAF's and not 61MAF's. Does this surprise anyone else? 
OK, so I am now hacking my 63MAF to go on my 61. Well, that change alone will permit more air. But about hacking: I removed the oval screen, which doesn't seem like a great advantage, but I rely on the words of others. I dug out the wax on top, revealing a screw which protruded into the air flow. So, I dutifully removed the screw. More air space.
But why stop there? The ovalized air flow chamber is separated into two compartments by a vertical wall about 1/4" thick (plus another small section at the top). Why not remove all obstructions within the oval space?? Am I missing something here, because I have never read about cutting out the insides.
This could easily be done by inserting a hacksaw blade in the chamber, attaching the saw handle, and cuttung away. A file would take care of the rough edges. If I am off-base, someone please tell me. I am planning on trying this.
Bill Spruill, oldest Colt, not the smartest 
Well, now I'm embarassed. I found the answer at