Originally Posted by ForceFed86
After running a new personal best first run out. I broke my rocker pedestal. Then I Found some more disturbing carnage. aft and middle rocker pedestals are cracked. Strangely the fwd rocker is the one that broke. Think this is something I should try to tig repair on the car? Or is that a bad idea because it's iron? And ideas?
This is the middle, it's not so bad.
The aft is the bad one.
This low rpm 3.8 went 10.24@133mph @ 6200 rpm with a 26" tire. Assuming I can fix the rocker pedestals. I plan on going to a 28" tire to lower the rpms.
Ouch, can you say new head. But 10.24 @133 whoa dude talk about thumb's up.
You are discovering that the Chrysler shares a problem similar to the old Ford FE where the end rockers are hanging in space. This overhung load moves the end of the tube too much and it fatigues off after jerking the end bolt around pretty good. The solution is to press fit a piece of bar stock into the tube. Gun drill it lengthwise about 3/16ths inch for oil and drill in the bolt locations. This will stiffen the whole tube which will allow the overhung moments to be shared by all the fasteners.
There's no really good fix for the end pedestals once cracked as they are already overloaded, the "solid" core to the rocker shaft helps a lot but not enough to overcome the already existing crack in the pedestal.