[crossy]

[QUOTE=Ivan D.;2413879]I have some weird Offenhauser intake in my 350, tis a split-port runner design (about 1:2 ratio) and the primaries feed the smaller part whic theoretically keeps the airspeed high. This intake design is good for low-rpm torque and supposedly dies up high, but hey, my usual operating range is 1000-2000rpms so I really couldn't care less how it flows at 5-6k. Now I don't have actual sheets with the old and the new intake data, but the butt dyno tells me the split port design works well for what I want from it - honestly, at 2k rpms the truck feels like it can climb vertical walls! I've been told that this whole split-port deal is an outdated concept.

Nah. that Offy 360 was a GREAT intake, ugly though and cheap if you find a used one because of that.
It was just too expensive when new. they were great intakes. did some testing on 1/4 mile way back when on a 351W in a heavy truck and it was the winner hands down. ALL full-size trucks are heavy. BTW, the Offy 360 weighs nearly as much as a cast iron intake because of the internal design.
just so you know a normal performer will NOT out perform an early cast iron, non- EGR intake. I find them cheap at swap meets but i would never pull a cast iron to install a regular performer unless it needed it or I was re-doing the engine. The performer has port design to fit a variety of head designs and is a money making compromise for edelbrock.
crossy