What is the timing and distributor marks on a 1970 Buick Riviera 455 cubic inch?

The timing marks for a 1970 Buick Riviera with a 455 cubic inch engine are typically located on the timing cover, with the timing pointer aligned with the harmonic balancer. The factory specification for initial timing is usually set around 4-8 degrees before top dead center (BTDC). For distributors, the 1970 Riviera commonly uses a Delco-Remy distributor, which is vacuum-advanced and features a mechanical advance mechanism. Always refer to a service manual for precise specifications and adjustments.