I am getting the Edelbrock 64cc Performer RPM Heads, and I need .100" longer than stock hardened pushrods.

I just want to make sure the Edelbrock 9629 hardened pushrods (.100" longer than stock, 5/16" dia., 7.9" length) will work with my heads and Comp Cams 1412-16 1.52 Mag Rockers (rocker stud size 3/8")

The rocker stud size is completely different from the pushrod diameter, right?

Quick help would be much appreciated. I need to get these order by tonight.
Thanks,
Brian

If that's what Edelbrock recomends, then get the .100 longer rods. Regardless,..there's a $5 plastic tool you can purchase from your speed shop that will check for correct valve train geometry,..and double check to make sure those over-length rods are what you need. Get it,..ask the counter help how to use it (easy). Money well spent.

Your rockers will work fine

Rocker studs and push-rod sizes/diameters have nothing to do with each other.

Agree with straightline, as long as your heads are threaded for 3/8 studs your good there (they should be, and edelbrock can confirm), but unless you have checked your pushrod geometry, dont take for granted that you will need .100 for sure.
The checking tools are cheap, easy to use, and very necessary, anytime you change valvetrain hardware that impacts your geometry. If its wrong lots of damage can become of it, worst case losing a valve in the motor.

If it were me, I wouldnt be buyin pushrods til it was measured. I never understood why cylinder head or cam makers or anybody reccomend a particular length pushrod for anything cause there is no way to be sure til you check em. Its good to caution buyers that they may need non stock length pusrods so your prepared to change if necessary. But its a little crazy to try and guess at the right length. In a perfect world those heads would be able to use the reccomended pushrods(easy right)....but if your using different "anything" than they may be expecting......things change. Just differences in machine work alone can change things about the needed length. Not to mention that the rest of your valvetrain hardware could change things too. The magazine articles can preditc the extent of your machine work or what parts your using. So, if you were to buy them, and then measure, only to find out they arent right...youve got pushrods you cant use. Or you can choose to use them and just deal with the fact that there will be pre mature valvetrain wear.

So, you can order the reccomended ones and risk them not actually being the right lenght. Or you can check up front to be sure. And once you get it right, the valvetrain will be more stable and last longer.

Sorry for the rant. It just bugs me a bit that many advertise the way they do.....cause they make it sound easier than it often is. And if its wrong, thats unnecessary wear and tear on the stuff that we have to pay for. So if you do what is normally the smart thing and listen to the manufacturers reccomendations....you could end up with poor valvetrain geometry. They should tell it like it is and let people know to measure, rather than reccomending parts that may or may not harm the stuff we just bought from them.

Thanks guys.

I'm not understanding what my current pushrod length has to do with the size of my new ones. Since I will not be using my current rockers, lifters, cam, valves, valve springs, heads, intake manifold, etc; how could my current pushrod/rocker/head set-up determine what size will fit in my new set-up?
It would make more sense to me if I were using new heads with the stock rockers. Then measuring the length of the current pushrod would seem more crucial in order to get the right size.

I'm not doubting you guys, you all know more than me. I'm just trying to understand all of this better.

Thanks for the help,
Brian

I may not be following you here, but the fact you are changing stuff is exactly why you need to check pushrod length not size. 5/16 (diameter) is standard and will be fine.
Things that affect pushrod length is longer valves specifically, as well as rocker ratio changes, but block decking, head surfacing, head gasket thickness all can add up requiring a longer or shorter than stock pushrod.
Why do you say you need .100 longer? Was this a manufacturer reccomendation? Because as Gregg points out, there are too many variables to say "you will need X size pushrod", they should just say, check to confirm length needed.
Does that make sense?

Install and torque the heads,..drop a couple of lifters into their bore and then a couple of the pushrods you have now (stockers?). Then while the lifter is on the flat part of the cam, use the plastic tool I was speaking of earlier. You put it in place of a rocker, then you can visually tell if you need a longer or shorter pushrod. Hard to explain, but once you see the tool, it will all make sense.

Again very easy,..but very necessary,..there are at least a half dozen variables that will impact the length of pushrod needed,..part of the fun of aftermarket parts,..making them all work together.

Sorry I wasnt more clear. What I was saying is that you should get all of your new stuff on there(dont measure with all the current stuff like heads and such....measure the new stuff)...and then by using a pushrod length checker, measure out what pushrod length you need to finish it off right. So after the new heads are bolted up with the rockers your usin and everything, take a measurement with a good adjustable pushrod length checker. This will show you what you definitely need for a pushrod length instead of betting on the reccomendation.

Edelbrock sells completely assembled ready to bolt on heads. They do in fact INSIST in .1" longer than stock pushrods, I ASS-U-ME because the valves are longer than stock.

Checking such things is always a good idea, particularly if you have a small basecircle cam, non-standard height lifters, weird gasket thickness, milled heads, or a heavily decked block.

I you choose to ASS-U-ME, then ASS-U-ME the poeple who built the heads know what they are talking about, and buy the .1" longer pushrods.

No way somebody (Vic Edelbrock included) can recommend the correct length pushrod without checking. Again, there are too many variables,..lifter differences, head gasket thicknesses, has the block been decked and decked again, etc.