Intake question for the engine guru's....

[tx69gmc]

Hey all-

I am in the process of upgrading the top end of my crate 350. Here is what I am going to use. GM Vortec heads, Comp Cams XE268H, Edelbrock 750, 1.6 Roller Rockers. My question is on the intake. Currently, I have stock heads and cam with Performer RPM and Edelbrock 650. Truck seems to be sluggish off of idle. Would this be due to the RPM intake? Am I robbing low end torque by using the Performer RPMintake. I was planning on using a Performer RPM on the new build but was wondering if the standard Performer might be a better torque choice. Thoughts???