S&S, Taque guides for Shovelhead and Evo

Polished.
It allows you to use the improved hydraulics of the Evo taver in a show.
When adapting these Billlet aluminum tachy blocks to a shovel engine, you must use 86-99 Evolution Big Twin hydraulics, an Evo-style camshaft and S&S quickee thrust rods.
If you wish, you can grease the upper end through the thrust rods (with Quickee 512497), Evolution style, when using S&S Showl rollers (512493).
Note: An Evo cam will have a reduction of around 9% in valve elevation due to the lowest S&S SHOVELHEAD (1,5) rocker ratio, compared to the original EVO swinging ratio (1,625).
The standard rocker's ratio of the Shovelhead rockers is 1.43.
Note: Adjustable thrust rods are required.
Retainers/clips/thrust rod fixers 512511 are also required when Evo 512494 style pushing blocks are used for Shovel.
Because these blocks of tachies are longer, a shorter retainer is required of 2,800 "long to achieve the correct tension of the spring of the thrust rod.

It adapts to:> 66-84 Shovelhead (NU). With Evo taites, cam Evo, thrust rods s & s quickee for easy installation