I hear what seems to be pushrod rattle noise from drivers side of motor. I've read that tends to happen to pushrods over the heat riser on the exhaust manifold-or is that a old wives tale?. The valve lash are non adjustable . I want to replace the rocker arms/pushrods and bridges in that area. I assume all I do is remove the old parts-put some assembly lube on them and adjust torque bolts to specifications. Should I get the valves in the closed position and off the cam lobes or will the hydraulic lifter lash compensate when tightening down the bolt- I;ve seen 25 and 35 ft lbs referenced. Does anyone have a factory specified torque they can share. Thanks in advance

 

Yes, position the valves to both be closed on the cylinder you are addressing before removing the rocker assembly. Lube the new parts, assemble and torque in place.

No I've not heard of the closer to the heat riser being a problem, perhaps if it was stuck closed it could be though. Have seen problems with parts e.g., valve guides closer to the EGR valve but a '68 didn't have an EGR.

 

Torque values are listed in the "BIG BLOCK" section of these forums as a "sticky". Doesn't matter big block or small block as the only difference for your year motor is in the main bearing cap torque value. 25 lbs/ft is the correct value for the rocker arm bridge bolts. Let us know what you find.

 

I have not seen a lot of them over the years but every time it was the rocker arms aluminum bridges worn out.

 

X 2 I tend to agree with BILLK. The push rods are either straight or not. You may want to check if you are getting oil up there.