5.2L V8 Mods

I want to improve performance on a stock 1986 318 5.2L V8 I have. I've been looking at specs for this engine and 150HP at stock seems weak for a V8. The truck has been sitting for a long time so I changed the oil, oil filter, and air filter and right away noticed more power.

I've read the cheapest way to gain HP is from installing a high performance air intake. What air intake should I look for? I found a picture of an air intake on a 360 on google. Is this what I should install?
http://memimage.cardomain.net/member_images/5/web/485000-485999/485035_60_full.jpg

Also if I install a better carburetor will that give me a large performance increase?

I'm basically looking for cheap horsepower, and just need some good helpful advice on what I should look into. Thanks, hope to hear from some members. :)