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Discovering a new redline for engine after a rebuild

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This may be a question for engine building as well, kind of a hybrid of both ends of the performance car spectrum. After building an engine, whats the best way to determine a new redline?

Example: Closed deck block with lighter rods and pistons and a head with larger cams and higher RPM-capable springs. What can help determine the new safe redline? I was assume you limited by your weakest link but is this something we determine based off of what the part manufacturer recommends if that data even exists?

The rev limit in terms of mechanical strength will depend on the quality of the components you've used in the build, the mass of the parts and the stroke of the crankshaft. The parts need to be chosen with your final rev limit in mind and be strong enough to handle the forces involved.

Just because the components can handle a certain rev limit however doesn't mean that you should rev your engine that far. This really comes down to the engine's ability to breathe efficiently at high rpm. An ability to operate efficiently at very high rpm relies on the intake manifold and head flow, cam profile and exhaust system all being optimised with that aim in mind. As a general rule of thumb I aim to rev an engine 500-1000 rpm beyond the point in the rev range where we see peak power (assuming the engine components are up to this task).