You will not gain 150hp by removing smog. That's just nuts. The stock 4V intake is quite good, running very close to the Edelbrock Performer RPM AirGap until rpm's go above 5,000rpm, and unless you go with a hotter cam, the stock intake is all you'll need. The stock 4V intake can trace lineage all the way back to the 1968 340 Magnum 4V intake co-developed by Chrysler and Edelbrock. The stocker is about 15hp shy or the AirGap at 6,000rpm when tested with a considerably hotter (streetable) cam. That shows just how good they could be even 40+ years ago. If you wanna lose a few pounds, yeah, go aftermarket, but the stocker is free and awfully good. Actually, with modern cam profiles a 6K rpm 360 can easily use the 800-900 cfm carbs out there. An aftermarket (Speed Demon)750 is fine for max effort with essentially stock heads, towing or mileage calls for a 650. Have the heads cleaned up with some mild port and polishing, install 2.02" intake for max power to 6k rpm's, keep the 1.88" for lower performance choices. The typical 360 LA stripped of smog will show around 250hp at the crank. You can add 100hp without even trying, mostly with just the cam and some carb tuning/open exhaust. This article is on a 5.9 Magnum build, but the LA build is very similar.