Will 454 engine fit 4th generation camaro?

No, a 454 cubic inch (7.4L) big-block Chevrolet engine will not fit a 4th generation Camaro (1982-1992) without significant modifications. The engine bay is simply too small. While some people have done it, it requires extensive fabrication and is a very involved project. You'd need custom headers, motor mounts, potentially modifications to the firewall and body, and likely a custom cooling system. It's not a bolt-in swap by any means.