Thread: What Length Pushrod Needed

Tweet

Am putting a 350 together with Edelbrock E-Tec heads and edelbrock roller cam in a '68 block. Using summit aluminum needle bearing rockers and edelbrock roller lifters.

Bought the tool to measure for the push rod length...but nothing has any instructions!

I know the rocker arms have some adjustment in them, and these have a locking hex bolt inthe middle to lock the adjustment.

What i need to know, i think, is where to start the rocker arm at to measure the push rod length....

thanks for any help here...totally lost i am.

chris

Lifter on the heal of the lobe, rocker tip on the closed valve end, rocker adjuster in the middle of it's travel.

Hey Chris,

It's not really a matter of how far you screw down the nut, it's about where the roller sits on the top of the valve stem. You should screw down the rocker so that the roller is positioned approximately 1/3 of the distance from the center of the valve stem on the intake side. But more importantly, you want the roller to have the least amount of travel (from end to end) as possible as you want the most pressure to be in the center of the stem to prevent guide wear. Here's a nice article to follow for checking pushrod length. It should answer all of your questions about proper pushrod length and how best to measure...

http://www.compcams.com/Technical/Products/Pushrods/

I have the stock (7.8"?) rods from another 350.
the 'details' say "The use of retrofit lifters may require the use of special length pushrods"

I put the parts toghether as you say - and without collapsing the lifter and the stock length rod allows the rocker stud/nut to go one about 1 to 1.5 threads - and there is no clearances at all (as i expect there should be with the valve on the seat and the lifter on the 'heel' (base circle).

Rods can be had .5" shorter, in .1" increments.

perhaps take a stock motor (have a 305 laying about) and measure ho far the stock rod protrudes above the head or some such place and try the same distance measurement on the fortec motor?

i don't have the summit receipt in front of me, but we got there version of edl-97383 - the edelbrock lifters. the edelbrock ones are not in stock, and the summit ones are $20 cheaper and 'the equivalent' the sales weenie said. crane makes the same thing as well.

Don't know if you have one or not but Summit does sell a device that mimics a rocker arm. You install your adjustable push rod and then put the plastic pushrod lenth checker, or rocker arm thingy on and adjust your pushrod until the checker is flat againt the valve tip and then measure your pushrod. Then order the pushrods you need. I forgot the lenght of mine but they are quit a bit shorter than stock. I also have a roller cam and rockers in my motor.
Remember too that when you do buy your push rods buy about 4 extra, since if you bend one you will have an extra on had right away instead of trying to buy one via mail order.