My plans to modify my Silent Choice to play well with Lightning headers is probably not going to work - there simply is not enough room in there. Plan B would be to go to a full time muffler, muffler tips, or switchable tips.

I have seen a few sets of the Corsa full time muffler tips for sale. Has anyone seen a change in RPM by adding or removing a set of these? Looking at them, I can't see how they would not restrict exhaust flow.

I have also considered the tips that have the corkscrew design. Anyone had experience with these on a HP setup? These are going to be behind a warmed up 489.

I called Corsa and was told no power loss at all..

I also removed corsa tips from 7.4s and added straight tips and noticed no diffrence.

They have different sizes so make sure you get the right ones for your application (6" and 6.5" can size are the larger ones, I believe). I put a set on my boat that came off a Formula w/ 525EFI's. I noticed no difference in RPM or speed and I am very happy with them.