Re: {Chrysler 300} 300F Pushrods & Rocker Arms

Hello Fred,

Perhaps this will help, from my experience a year ago with my F motor -

I sent my motor for rebuild to a shop in Michigan that Michael Burke has used for decades. Referring to our Club's Tech Department piece on Cams, link - CAMSHAFTS -- WHAT? HOW? WHY? (chrysler300club.com) - I purchased a new cam, lifters and pushrods from Hunter Webb at Camcraft, as recommended. These are the pin-type pushrods and lifters used in the Hemis and earlier Wedge motors. My block had been bored .030 over, and this latest rebuild opened it to .040 over with new pistons and a variety of other parts.

When I got the motor back and we (mostly with my local oldtimer mechanic's help) reinstalled, primed and briefly fired it up, there was some audible noise coming from a few of the pushrods. Some of these pushrods were a bit too long. Then we were suggested to try the ball-type pushrods and lifters used in the later Wedge motors. These pushrods were said to be slightly shorter than the earlier pin-type style. Installed those and we still experienced noise from a couple of the pushrods.

When we picked up my rebuilt motor, the old pushrods were returned with it, along with misc. other items. We saw that these old pushrods, installed by George Riehl when he rebuilt my motor back in '05, when I purchased my F, were ball-type "adjustable" pushrods. We then left the ball-type hydraulic lifters in the motor and re-installed these ball-type adjustable pushrods. Performing the appropriate cylinder by cylinder tweaking of the lengths of these pushrods did the trick, and the motor has been running great the 5,000 or so miles I've logged on the car since last August.

Not having a micrometer, here are my measurements, 'eyeballing' them, with photos of my spare parts attached -

Original pin-type pushrods
- Length - 9 3/8"
- Pin head - 3/16" diameter of pin shaft
Later style ball-type pushrods
- Length - 9 5/16"
- Pin head - 5/16" diameter of ball

Hope this helps! Have spoken with Timo in the past.

Noel

On 07/31/2023 10:06 AM CDT Frederick Grossi <e55grossi@xxxxxxxxx> wrote:

Hello Group,

I am having my 300F 413 engine rebuilt by Timo Tanskanen, a restoration expert who regularly advertises in our newsletter. He has some questions about the pushrods and rocker arms of this engine that he has asked me to pose to the group because he has run into some issues that are causing delays in my engine rebuild. He states that the factory manuals don’t seem to have clear enough information and all of his “go-to” guys can’t seem to be able to say for sure, have moved on or passed.

Basically, Timo would like to know if anyone has a good photo(s) and/or clear specification info regarding the original pushrods and rocker arms.

1. What diameter are the upper and lower pushrod tips originally used in the early RB (383/413) engines? Photos?

2. What is the OEM cup size on the pushrod side of the rocker arms, 1/4”, 5/16” or is/was there possibly two different sizes available for/used in early RB engines? Photos, especially if two different sizes, preferably shown side-by-side in resolution photo or two?

Thank you and much appreciation,

Fred Grossi

Pegram, TN

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