S&S, Tacho Guides for Shovelhead and Evo

Polished.
Allows you to use the improved hydraulics of the Evo tappets on a Shovel.
When adapting these billet aluminum tappet blocks to a Shovel engine, you must use 86-99 Evolution Big Twin hydraulic lifters, an Evo-style camshaft, and S&S Quickee pushrods.
If desired, you can grease the top end through the pushrods (with Quickee 512497 pushrods), Evolution style, when using S&S Shovel roller rockers (512493).
Note: An Evo cam will have about a 9% reduction in valve lift due to the lower S&S Shovelhead rocker arm ratio (1.5), compared to the stock Evo rocker arm ratio (1.625).
The standard rocker arm ratio on Shovelhead rockers is 1.43.
Note: Adjustable pushrods are required.
512511 pushrod retainers/clips/fixers are also required when using 512494 Evo style tappet blocks for Shovel.
Because these tappet blocks are longer, a shorter 2.800" long retainer is required to achieve proper pushrod cover spring tension.

Fits: > 66-84 Shovelhead (NU). With Evo tappets, Evo cam, S&S Quickee pushrods for easy installation