i have an 87 sc with a 350, heres what i have so far.
edelbrock performer intake, edelbrock 650 carb, edelbrock open element, elelbrock highflow mechanical fuel pump, dynomax shortie headers, custom y pipe, 3 inch flowmaster american thunder cat back, 160 degree stat, no ac, gutted front nose, turbo 350, and 3.42 rear end gears. i figured i was pushing about 250 horse but im really not sure. the engine was an 86 350 crate motor. i was thinking cam should be my next mod but what should i use for my setup? thanx

 

I'd say go with headers.

edit: oops, Just noticed you had headers. A cam sounds like a good idea. But I would probably do some suspension mods.

 

A cam.

You need to get that .390"/.410" POS out of there. I'd suggest one of the Comp XE cams, either the XE262 or XE268 depending on your converter. Stock converter = 262, higher stall = 268.