408, Small or Big Block? Need EGT Info

I know the 360 block makes it a small block, but the 408 insides make it a big block. I didn't know which category to post this question in.

I got the EGT to keep an eye on the temps. I am making modifications to the engine and need to see if the engine runs any hotter with the mods or not. I don't know how I am supposed to keep an eye on my dizzy curve. But I have an AFR Gauge. I know reading plugs is important but they don't tell you what your EGT is when you accelerate vs cruise. Cruise at 40 vs cruise at 70, know what I mean? I keep an eye on the plugs for back up, to verify that my instruments are not way off, but I need to get a feel for what the engine temps are running at at various speeds.

I have an MSD dizzy, I put a 14 bump stop in it per advice. If I run with the medium silver and blue spring, it is very spicy, so I went with two medium silver springs and it still runs great, but not so spicy on acceleration. I'm not drag racing, but I do step on it and will be making chassis dyno runs. With that said, I am not looking for 5hp differences, I am looking for big ones, once I get significant bumps in hp, then I can fine tune, but I am experimenting and don't want to burn my motor up. So basically, what is a normal EGT Temp and what is too hot, what is dangerously hot?