Just want to know if the 250 can run great on 454 .030 oversize with one 1050 carb?

Center carb mount plate or forward offset carb mount plate?

Also any problem or advise with that blower?

525sc is a 454 with a 177 and a 1050. I think it will work

Yes, that will work well.

Probably Center carb plate to keep fuel distribution the most even.

Another question about the B&M 250 blower, I have see two diferent blower to intake seal setup, one with a gasket and the other with oring.

What is the best between this two blower to intake seal setup?

Use the gasket, it seals better than the o-ring. Also, use the forward offset carb adapter. With the center carb adapter, the front cylinders run leaner than the backs, and that was with squared jetting.

And finally, yes, they work great on a 454!!! 600-650HP depending on the build, maybe even more.