I changed the valved springs and installed the cam this is on an 03 I am tinkering on. I have heard so many different opinions I do not know what direction to go. The heads are bonestock and have not been milled any. So do I go with stock length a hair longer or what. I am for sure wanting to go hardened route as opposed to the oem's. By my way of thinking if anything the LS6's use taller valves so they can use standard length LS pushrods. Could I take the difference in valve height and then in turn add that to the length of the pushrods to make up the difference since the 5.3 truck valves are shorter.Any help is appreciated. Thanks

 

Get a pushrod length checker and measure.......

 

I don't mind going the checker route but I figured somebody here was bound to know exactly what I would need since this has been done for quite some time already. Anyone have a canned this is what I need ..... Thanks

 

7.35 but but, you could prob get away with the 7.4's

John

 

I went with 7.4, as have many. No problems or noise here. I think you jsut lose a few thousanths of preload in the rocker.

 

I recently installed the Comp XR265HR which is very similar to the Zo6 cam and heres what i found. The Comp cam base circle was .055" smaller then my stock 5.3L cam, That would put the radius difference (pushrod length difference) at 27.5 thousandths (.0275" ) I milled my heads .025" to compensate for the difference (and to boost compression) and used stock length pushrods and everything went together exactly as it came apart (lifter preload etc). Have a scosh of valvetrain noise but not bad. Been told the Comp 918's are a bit noisy as they are so much stiffer than stock. I am pretty sure the Zo6 Cam is almost the same base circle .050" i believe. So that would put you at a difference of .025" So to retain stock valvetrain geometry you would need 7.425 pushrods. Just my two pennies-

 

Thank you a bunch. after sitting down and doing the math. I came up with 7.405 being the difference. So 7.425 is perfect I just wanted to clarify I knew there had to have been a few guys that have done this. What are the stockers for length 7.4's?

 

I just did a 02 ls6 cam in my 6.0 and went with the the 7.425's and the valve train is super quiet.

 

I used 7.425 and every worked out great