Where is my redline?

I have MSD 6AL box with a 6000rpm chip.

I don`t push it past 5500 rpm though, its just asking for trouble.

Im not certain where the stock redline would be considered, but 5500 would be a good baseline. But the redline on a stock bottom end would be around 6000....not that you cant exceed that, but your camshaft probably won't allow you to pull much higher than that anyway. The redline will ultimately be determined by the powerband of your camshaft. Just run it up to when it stops pulling hard and that will be your redline, I would bet that falls somewhere between 5500 and 6000. If its a hydraulic cam your valves will float if you turn too many RPMs and the engine will stop pulling hard anyway. Lots of stuff I left out, but i try not to get too long winded.

it depends on the cam and the valve springs. the stock cam had a peak power of about 4500 rpm, and a redline of about 5000. aftermarket cams are all different in what rpm range they are designed to work in. stock valve springs however usually limit the engine to about 5500 before you start getting into valve float, but you will feel the engine nose over and stop producing power before that happens.

If, as you say, the engine is stock, there's no point in going above 4500. There's no more power up there, and you risk catastrophic engine failure for nothing.