I have been considering installing a set of roller rockers in my DD (1994 F150 with an all stock 351) for a while now, and a NIB set of crane RR came up on a local swap site recently but before I jump on them I have one hesitation. The engine does not and has not in the past to my knowledge have any mechanical issues, idles well and has good power. It also has 166,000 miles of service. I am not a fan of disturbing things that work, and I am concerned that 1.7 ratio rockers will put more stress on the lifters, push rods, and springs and that something will be more likely to give. I realize the change is marginal but...

I would appreciate your thoughts on the matter.

I will also be posting in the 97-96 Truck Forum.

 

Unless you run up to 6000 rpm constantly, i don't think the 1.7 rockers will stress your valve train much. If it does while you're driving sanely, then they probably needed a valve job anyway, which would be a great time to install stiffer springs.

 

Thank you for your input xlt4wd90.

 

If done this swap many times on high mileage engines, nothing negative ever happened. The rockers used were also high mileage (Cobra 1.7's bought used) The ones in my 96 E150 have were bought used with 100K miles on them and have been in 3-4 different builds since I bought them. Damned things last forever seems like .......

 

Thank you for sharing your experience!

 

I also bought a used set of the Cobra rocker arms and examined them carefully. Somehow the previous moron (oops, I mean owner) had managed to crack several of the pedestals. Luckily I was able to order a new set of pedestals at a quite reasonable price through a local parts store.


So as with any used part, examine very closely.

 

I bought a set of used Cobra roller rocker arms as well, but discovered that the previous moron (oops, I mean owner) had somehow managed to crack several of the pedestals. Luckily I was able to buy replacement pedestals for a good price at a local parts store.


So whenever purchasing or installing used parts, examine them closely first.

 

Computer glitching, deleted my post then it reappeared, thus the double post...

 

The pedestals have a Y-opening that the trunion bolts down to. The instructions say to tighten the the bolts to about 25 lbs-ft. If you tighten the bolt too much, you will split the pedestal.

 

...and some people in lieu of a torque wrench seem to use the method of "tighten it until it breaks, then back off half a turn".