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Drivetrain => The Nailhead => Topic started by: Chris on February 20, 2012, 04:56:37 PM
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Anyone here use adjustable pushrods on their nailhead?
I have a set sitting here and I'm debating if I should use them or not when I replace the lifters in my convertible.
Here are the questions I have about them:
1. What are the advantages and disadvantage of using them?
2. What is the appropriate way of setting / adjusting them?
3. Has anyone had problems with them?
4. Any preferences for lifters?
Thanks,
Chris
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Hi Chris,
I have not used the nailhed adjustables, but I know Wild Bill has them on his Topcat 66 Wildcat. He had some trouble getting them working perfect with a solid lifter set up, bu I think with a hydraulic they would be set and forget...I have em in my 455 Wagon and have been well pleased with adjustability and performance.
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I have a set on my blue 66, been in there since I rebuilt the 425 when I was a teenager! No problems.
Disadvantage would be cost and the extra weight. Tho I never weighed them, so I can't say if the difference is significant.
They are somewhat difficult to adjust, but with a pair of modified wrenches, it's not too bad.
Hydraulic lifters are self-adjusting to a point.... generally 0.020 to 0.060" preload will work.
If an engine is rebuilt, the necessary pushrod length may change outside of those limits.
Changing from a stock thin steel shim gasket to a thicker composition gasket will add 0.030".
Installing a reground cam with a smaller base circle will also add extra clearance.
Having the heads cut, block decked, or even a valve job will decrease the necessary length.
My best advise would be to use a pair of adjustables to check the necessary length, and compare to the original length. Then decide.
Johnson lifters were once considered to be the best. Not sure how current offerings compare.
http://johnsonlifters.com/ (http://johnsonlifters.com/)