What is a thrust button?

[Chris A]

On a 400 what is the proper way to install a cam and timing chain assembly? It is just sprocket to cam then washer and bolt right?? I read something about the "thrust button" and wonder what this is all about and if it apply's to the 400. Thanks

[sixpackguy]

A cam thrust button keeps the camshaft from "walking" in the block, or in other words, moving to the front of the block. Generally this is NOT a problem with hydraulic or flat tappet cams. It usually only occurs with the use of roller cam and lifter setups. For your 400, unless you're putting a roller cam in it, don't worry about the need for a button. If you do need a button, it goes in the hole in the end of the cam in center of the gear, and goes up against the timing cover when everything is bolted together.
Hope this helps....

[Chris A]

Thanks. I didn't think I needed one but wanted to make sure.