If you burn your own chip, is it possible to gain any hp on stock 350 map with full exhaust, afpr ported plenum? Or is it to hard to do it? I already have a performance resource chip which causes knock retard on higher rpms acording to scantool. They said that i would get 25hp so i´m losing hp instead.....

You could gain a few HP on a stock engine, and a few MPG too, if you play around with it long enough (or already know what you are doing).

Doing chips will allow you to optimise whatever you have to the level of tuning you can achieve.

Given time, and there is some knack to this, you can get it right, but learning is an individual thing, some guys pick up tuning almost overnight, some take years to get it.

If your triggering the K/S then that typically takes out almost 2x timing as needed. ie if you see 4d on the scan tool you have 2d too much timng, or can be a lil lean.