I am building a 5.3 for my iroc. I am using a comp cams 7702 length checker. I noticed that my exhaust pushrod would be small then my intake. Is this normal? Should I still run the same size rod? Also, what is a good preload with possible supercharger later on?

 

Preload depends on your lifter and can range from .020 to .080. I have to use two different pushrods for intake and exhaust to get the .035 preload I was looking for.

 

So my intake @ zero lash is 7.275. Exhaust @ zero lash is 7.3.

I am running a ls9 cam and ls7 lifters. What preload should I go with?

 

Preload on LS7 lifter is: .075" I would go with that preload on the exhaust and use one size pushrod on all the valves (.050" on the intake will be just fine)

 

No one else with an opinion? I was thinking about going with 7.375 rods

 

I could be wrong, but aren't you supposed to measure the pushrod length at zero lash, then add you preload to the length to get the size you need? I also believe your supposed to use a solid lifter or checking springs on your valves so the lifters don't bleed down when your attempting to take measurements? Maybe someone else could clarify a little better?

 

yes, find zero lash with the PR checker.. add desired preload amount to that...

In you're case I would run 7.350 PR's and it will give you .075 preload on the intake side and .050 on exhaust side.. ls7 lifter's are typically ran .050-.080 on average so you are still well within that range..

 

This was gonna be my answer as well. This fine gentleman saved me from having to type it out.

 

Awesome. What rods would you go with? I am leaning towards comp cam hi-tech 5/16" .080.