What does not need to be replaced with a new flat tappet camshaft?

When installing a new flat tappet camshaft, lifters typically do not need to be replaced provided that the existing lifters are in good condition and have not been worn down or damaged. Lifters are designed to work specifically with the camshaft profile they are paired with, and when reusing them, it's essential that they have been functioning well with the previous camshaft. Using the existing lifters can save time and cost, as long as they are not exhibiting signs of wear.

In contrast, valve springs, pushrods, and timing chains may require replacement during such an installation to ensure optimal functioning of the new camshaft. Valve springs may become fatigued and not provide adequate pressure for the new camshaft profile, which could impair engine performance. Likewise, pushrods should be checked for straightness and wear, as using new ones can enhance lifter to camshaft engagement. Timing chains can stretch or wear over time and may not be capable of maintaining the correct timing with the new camshaft, leading to diminished engine performance or damage. Each of these components is critical to the overall function and reliability of the engine, which is why they are often recommended for replacement during a camshaft change.