Seems I've read somewhere that there could be clearance issues when using these together. I just installed a set of TA 1.6 roller rockers with my 5/16 adjustable pushrods (`73 455). I followed the instructions that came with the roller rockers, and made sure each adjusting screw of each rocker was either even with the bottom of the rocker or very slightly protruding (out the bottom). I set preload of each lifter to between 1/2 and 3/4 of a turn on each. Both rocker shafts are shimmed (~.035") due to valve tip heights range from 2.126" - 2.143". I have not run the engine yet (snowing), but want to throw this out before I do. Thanks.
Need to highlight one of the statements above. The 1/2 to 3/4 turn lifter preload adjustment I referred to above was done by turning the rocker adjustment screw (not the 5/16 pushrods). Is this the correct amount of preload? I'm sure the threads per inch is different between the two with the pushrods being a finer thread.
I would adjust the roller rockers to the ideal cup position and then adjust pre load with the adjustable push rods then have some pushrods made up in that length. Measure all and average them out and have some made up in that length from TA. I don't like the idea of 32 adjustable (and loosenable) things under my valve covers.
Here's what I did; first I installed everything with close guess pushrod length, then installed the rockers and set preload. I then removed the rockers and checked the adjustment screw alignment with the bottom of the rockers. I then reduced or increased the pushrod lengths as needed so the pushrod side of the rocker adjustment screw would end up flush with the bottom of the rocker or slightly protruding. I also took a measurement form the top side of the rocker to define what measurement it needed to be for a flush position on the bottom side. This way I could verify the position after things are installed. I have all the pushrod lengths recorded in my Buick Diary. Still not sure about the pushrod to rocker interfearance, and preload (1/4, 1/2 or 3/4 turn) using the adjustment screw in the rocker? EDIT: I just talked to Mike at TA he said anything between 1/4 and 1 turn is usually fine. More specifically if you are using adjustable pushrods make sure the adjustment screw is not recessed, this could cause interfearance. I looked again in the instructions and it says preload should be .030" - .060" and one turn of the adjuster screw is equal to ~0.50". Looks like I'm ready to roll. Should be close to 70 degrees this weekend, after the snow melts. :beer
