I snapped a rocker arm right in half, I was comin back from a wheelin trip and on the freeway goin about 3000 rpm's my chev 350 starts poppin, I pulled over, it would barely run. I couldn't leave it and didn't have commo so I drove it home 10 miles @ 35 mph) couldn't go any faster cuz my engine would sound like it was getting ready to take off. I got home and pulled the valve covers and my #6 (right bank) rocker arm was split right in half. I replaced it with one that Wheelinjp donated and it runs fine..What would cause a Rocker arm to go like that (it was a little worn) and what happens if it's exhaust and not an intake rocker.

they get fatige cracks in em...maybe you should check the others.

I would check to see if your cam has more lift then your valve springs can handle. You can get new spring retainers that give you a little taller installed height. Might want to look into that.

You've got a point there NE, I've got a Wolverine RV grind cam and stock springs......Cutter I'm going to replace all the rocker arms and NE I'll look into new spring retainers also......the rocker bushing had creases in it after the rocker arm let go from slamming into the head. Art Morrison should be able to help me out, their kinda spendy though. Do ya think Summit or Northern would have em?

Summit has all that crap, might try jegs as there a little more Racing oriented and have all that crap. Hopefully its just the Coil binding or a manufacturer error with the rocker arm. However I would check the Spring retainer to valve seal clearance and remember at 3000 RPM the valve has some momentum so without the engine there needs to be plenty of clearnance. I had a freind put a new cam in his ford and pull out 3 rocker arm studs :eek: I know Crane makes a complete kit of springs/retainer/locks that is designed for .500" lift on chevy heads. Also just remembered if you can find them there are offset Locks that use whatever retainer you want and move it up higher on the valve stem this also gives more clearance between retainer/seal

well luckily you got a rocker to replace it...........

if not you could have pulled the spark plug out and also pulled the other rocker off......and ran on 7 cylinders....

if you cam has no more than 500 lift you should be cool.....no binding...

if they have a lot of miles they might be a little worn......i would just replace the stock rockers with something a little better....

if you get better springs you might run into pulling rocker studs out.....or have to get new pushrods to have the correct geometry..

Well this engine (4 bolt main .020 over) has maybe 7000 miles on it, the 8 and 6 banks were tight and tend to tap not matter how I adjust rocker. The more I think about it the more I tend to believe that the days activites (snow run = high RPM's and cam floating) caused the rocker to stress fracture before I got it on the road. After about 30 miles @3000-3200 RPM's the rocker just gave out. When I looked at the pieces one side fit perfectly and the other side had a gap in it which would point to some deformation before complete failure..On a cast part that can only mean that one side was cracked for some time before the other side let go.
I'm going to replace all the rockers and check spring retainer clearance.
Thanks, Rick