Pushrod questions? HELP!!

[xracer22]

Hey everybody got some pushrod questions. To start with I am running a set of edelbrock performer rpm heads on my stock 89 rebuilt motor. The question I have is that edelbrock says i have to use there hardened pushrods with these heads because of them rubbing the guideplates, but the rods that they want me to use are 6.385 inches long versus the stock size of 6.250. Why are there pushrods longer than the stock ones? I have already checked my cleareance with the stock pushrod and had to shave a slight bit off the top because of there not being enough clearance. I dont want to have to do it again because of a longer rod. Do i have to use 6.385 inch ones or can i use shorter ones? Are they longer for a reason like because of the heads being taller than stock ones? Any help i can get would be great. Thanks guys

 

[Warbird19]

You need to use a sharpie or paint to top of the valve. Install one rocker arm on the intake and exhaust along with two stock push rods. rotate the motor over by hand and see exactly where the rocker arm is movie on the top of the valve. The reason for longer push rods is the new head could be slightly taller. You need to use hardened pushrods so they wear out the guides and not the push rods. But check the pattern where the rocker rubs the paint or marker off the valve. That will tell you if you need longer or shorter Pushrods, regardless then need to be hardened.

 

[liljoe07]

The reason they ask you to use a longer pushrod can be for a few reasons.

Head deck thickness.
Rocker pad hieght.
And the heads being a stud mount rocker setup.

As stated above, you need to measure yourself to be accurate.