Pushrod Wall Thickness
 

Evening everyone. Just wanted to check in and see what pushrod wall thickness would be best for the 467 stroker we are building. Obviously, thicker is better for a pushrod, but just wanted to get some opinions as to if something like a 5/16" .116" wall are really needed for this engine, or if the 5/16" .083" would be fine? The heads are 6X4, with Crower 68404 springs that will be set up at 1.550"-1.560" I.H. area, so we can get up around 125-130 lbs on the seat, as we are using the Voodoo 704 camshaft in this engine. Open pressure should be around 300 or a little over. Rockers will be factory 1.5 stamped steel, with ARP 7/16" studs and Polylocks. The pushrods will be purchased from Smith Brothers. Application is 100% street car.

Thanks!

Well.... I think I've found the answer to my own question Lol.... it's right there on Smith Brothers website. They advertise their One Piece 5/16" .083" wall good for up to 700 lb of Open Pressure, so that should be plenty good, as that is over twice as much as what this engine will have Lol

I went with the thicker .118”” wall 5/16” Manton pushrod on my relatively mild 421 HO build, 068 cam with 1.5:1 Crower stainless roller rockers and spring pressure around 250# over the nose.

Pushrod stiffness is most enhanced by using a larger diameter pushrod. However when you’re stuck with a 5/16” pushrod it can’t hurt to go for the thickest wall available.

Less pushrod flex is always a good thing.

A stable valve train ensures reliable performance.

To add to the above post.....

Do not be overly concerned about pushrod weight. The pushrod is on the slow moving side of the valve train. The additional weight of a heavy wall pushrod usually provides a much needed increase in valve train stability.

https://mantonpushrods.com/tech-info/facts/


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Thanks guys, after much research, we are still torn between going with the .083" wall vs going with the .116" wall Smith Brothers LOL. I mean, the spring pressures aren't outrageous, only around 128 lb on the seat with the Crower 68404 spring installed at 1.550", and around 310-315 lbs over the nose at max lift. Read many builds using the .080" wall just fine with more pressure than this, so I'm sure they would work fine, but on the other hand, we know the thicker the pushrod, the better, but then again if we don't need thicker.... hahaha.... there is about $40 difference between the two.....

Spend the extra $40.

You’ll sleep better. ;)

If only you could see a video of those pushrods flexing away.

Thank You! I appreciate it

Ditto. Run the thickest possible.