It didnt bog at all, just lazy. RPM's didnt climb nearly as quick. With the AFR's, you'd think the RPM would have given me more top end, but it didnt happen. Engine has the stock hyd roller with 1.7 rockers, so around .470 lift at the valve, BBK shorties, the performer with a port match, 80457s holley with jet conversion, 65/73 jets IIRC, 1/2in 4 hole phenolic spacer and the factory EGR plate and AFR 165 heads. And yes, it pulls right up to and peaks at 6k rpm with the HP. You'd THINK that with the higher flowing RPM intake, that I'd pick up on the top end at least...