Chev 250 mods? interior parts

[whole_f-n_show]

I was wondering if anybody knows of any simple and fairly inexpensive MODS that i can do to my Chevelle 250 1bbl motor to get a bit more horsepower out. Also, I would like to hear from anyone who knows where i can get new interior parts fo it since they are hard to come by in Minnesota. It is a 1976 chevelle malibu if that helps out

[redmalibu307]

2 thing that i've heard are better for the engine and increase hp and torque and arent that expensive is a header and a intake manifold