Hello. i recently had the heads shaved on my 400 ford by 25 thou. since it has the pedistal style non adjustable rockers wouldnt i need to adjust the valvetrain somehow? would shimming the rockers work and if so how far should they be shimmed? thanks!

 

also im running a comp cams 268h non roller cam

 

Is your cam broken in?

Do you have the stamped steel rockers or rollers?

Do you have and adjustable pushrod to check the length you might need and/or the geometry? Not so much with OEM rockers - there's some fudge room with them, but with rollers, it's a good idea. It's a good idea, anyway.

Have you checked the preload with the stock pushrods?

Trial and error with shims to get where you want to be... different length pushrods would work, too...if needed.

 

Check your valve lash first, but if you shaved them .025, then a .030 shim set should be what you need to get back the way it was.

 

. Actually, by shaving the heads, you prolly need to UNshim the rockers/lower them... see if there are any shims that can be removed... or if the rocker stands can be shaved, as well... otherwise, may need shorter pushrods to keep the lifter plungers from being pushed in too far... or pushrods from bending... valves never fully closing... however, the lifters may be able to absorb the extra .025" without bottoming out...

 

If you resurface your heads .100" it still will not effect your rocker arms at all.
Yes, you would need shorter push rods.
When you have a pedestal/ shaft type rocker arm system, you shim to obtain the proper geometry.
Hopefully the machine shop paid attention to your "valve stem height" This is what will mess up your geometry.
The push rod length will only effect the lifter pre-load.

1) Shim for geometry.
2) Push rod length for lifter pre-load. (push rod fills in the gap)

Now you must be doing this with oil in the lifters.
A dry lifter will fool you when it comes to your geometry.

 

. Yes, I was thinking backwards above... a shim under the rocker arm pivot may be enough to compensate for shaving the heads .025"... which prolly won't be enough to hurt rocker arm geometry/where the rocker arm tip contacts the top of the valve stem/contact patch... but a good opportunity to investigate just how far each piston is being pre-loaded down into each lifter and adjust as needed... with a performance cam, I like to see the lifter piston stay up in the high end of its travel range to lessen the chances of lifter pump up and the amount of pump up that can occur, to prevent valve to engine piston contact... and to quicken recovery from lifter pump up...

 

Ford used to offer shorter/longer pushrods by .030" I believe. Don't know if they still do.

 

Howdy all, I've been using the forum for some time now and it is helping greatly. I have a similar question as to pushrod length. I'm using a Edelbrock #2172 cam and am considering using 9.45" push rods on the exhaust and stock on the intake. Will I have any issues with this?

 

You might have better luck getting answers if you start your own thread.
To answer your question a little, yes, you will have issues with those length pushrods. I could elaborate a bit but if you've got this figured out, I'd be wasting my inadequate typing "skills."

 

I don't know why you would have to run different pushrods, I'm running that cam and stockers are working fine.

 

Stock = 9.500", yes. 9.450" on the exhaust with 0.510" lift - I can forsee preload problems.

351Cleveland C4: I'm glad they're working out for you.

 

Thanks guys and I appreciate the advice and comments.