I guess I don't actually KNOW the rect's are too big, but based on all I've read and the recommandations given for mild/street engine builds, they are always opted out for the oval ports. I guess you get better cylinder fill at lower rpm's because of the smaller intake ports while not loosing any breathability. My initial guess was I would gain a little compression and better cylinder fill, and as Nitro said, this would put my power down into a more usable rpm range. I just didn't know if it was worth it...financially.