I've done a search and I don't think this has ever been discussed here before. And I'll warn you now that this will possibly end up like the "car tire on a bike" discussions. Meaning there will be those who haven't tried it saying it can't be done and those who have done it saying it works great... and a few in the middle.

A few years ago I read a Popular Science article about a fellow in India named Somender Singh that had developed an unbelievably simple (and almost free) process to get better combustion (resulting in more power,better mileage and less emissions) from almost any engine. Here is a link to that article that first caught my attention... Popular Science article It is as simple as cutting a few grooves in the combustion chamber in the correct places.

I ran across this info again tonight and thought I would put it out here for anyone that may want to do some exprimentation. Especially any with SVS issues. I'll put some more links at the end for anyone wanting to do some reading.

If I ever have heads off I'll be giving it a try.

Somender Singh's website
Groove Theory
Photos of different heads with grooves