[wanab5150]

I did a long thread about 3 inch exhaust for Superformance. You might want to search for "Superformance Exhaust" in the search box. If I remember, there were a number of recommendations there.

Additionally, if your 418 has 351 stock port heads, stay with the 2.5 diameter. If it has AFR heads or a ported exhaust, OR HAS THE "402 HEADER"...go with the 3 inch.....my two cents. Hell, my Harley has 2 inch on just one cylinder!

I have the 3 inch packed Chambered exhaust brand mufflers on my small block 427 with AFR big port heads and wish I got the unpacked version. I've driven both. I can't tell any sound difference at speed or acceleration, but at idle they just make a meaner( but not necessarily louder) tone...much more deep.

If this is confusing feel free to call and i will explain the header, port, and exhaust issue to where it makes more sense...........916-791-7695 Happy hunting........tom