Ok let me go back and rephrase my first post....

File fit rings will always out preform pregapped rings if done properly!

While there is some hp to be had with the ring gaps I find 100 hp a little hard to chew. You serioulsy have to ask yourself though: How correct was the ring gap with the pre gapped rings?

For a modified street engine IIRC the rule of thumb to determine the ring gap is:

The top ring should be .0045 to .005 inches times the bore size (which on a 306 should roughly be about 4.030 give or take a little)

And for the second ring it should be .0055 inches times the bore size.

Oil ring gap is usually a constant at .015 inchs.

Whats the differance if you find a pre gapped ring at those specs or you file them yourself?