Is the stock 4V cast intake good to 6500rpm???

Is the stock cast-iron 351c 4V intake manifold good up to 6500 rpms?  The following article says so, but tons of people on this forum say 5500 rpm max.  Who's right? 

http://www.mustangandfords.com/techarticles/engine/mdmp_1110_supercharged_351c_cleveland_build/index.html

yes, this article has numbers for the supercharger too, but below is stock intake with XE284H camshaft and headers.

351C produced 447 hp at 6,400 rpm and 411 lb-ft of torque at 5,200

Thanks.
Jim

Jim