Olds 455 was a very good engine and parts are still available. The were the power plant for the 70 Olds 442 W30. They were also used in many marine applications. Lots of Olds 98's were cut for the engine. The best ones were in the early 70's. Later they went to a block with thinner cylinder wall thickness but that's a real issue unless you are building for all out performance. You can tailer the power to your specific needs.