That's really an outdated intake. Breadbox style intakes are good for high-rpm and/or boosted engines, but that Downs truck stuff is yesterday's news. Trickflow makes a good box style intake if that's what you're after, but you may be better off with a regular long runner style intake.
at only 10lbs a trickflow track heat or a edelbrock rpm II might be the order of the day. Match either of those up with some better heads and you will see a substantial increase in HP.