Stock pushrods work more than fine with the ls6 cam applications on the 5.3's.

It's been proven time and time again, by members, as well as performance shops putting them in.

 

Ya use the stock length pushrods, if you dont want .550 lift. There is a reason GM engineers used longer valves on the LS6, its because anthing over .525 lift on LSx cams has to be achieved buy grinding a smaller base circle. Otherwise you wont be getting .550 lift. Do some research. But use 7.425 pushrods.

 

Agreed i to have done hours of reserach and phone calls looking for the same information. The regular genIII cams are all mainly 19.7mm base circle, the 01 ls6 cam is 19.3mm, and the 02+ cam is 19mm. If you arent putting 243 heads on with the ls6 hollow stem valves you CANT use the same pushrods with out depriving your self of a shorter lift. So if you get that cam you need longer pushrods(7.425) and vice versa if you have the ls6 hollow stem valves with a stock cam the you will need shorter pushrods(7.375). I hope this information is useful.

 

thanks for all the information it is a big help i will be getting the longer push rods for the the install

 

FWIW, the comp magnum pushrods are a nice product. If you're doing the install, make sure to get oil inside of the pushrods before you install them. Don't just throw them in there without any lubrication inside them

 

good idea on the push rods hope to get the cam in by this weekend. how do you guys think it will run on the stock tune??? i will be getting it tuned asap just wondering about driveabilty

 

Your idle will be funky and you'll probably have some bucking problems. It's "driveable" on the stock tune but not desirable. One thing you might have to watch out for is Reduced Engine Power Mode. I'm not sure if the '03s have that problem at all, but if you trip the P0068 it won't start back up. The cam without a tune will cause you to throw a MAP and MAF performance failure code here and there.

 

ok i might send the computer out before the cam then when i get it back then i will install the cam

 

That's probably your best bet. Looking at the specs on the cam it won't be too bad, can't really tell until you put it in.

 

Can someone explain to me how a pushrod that is .025 longer can make a valve lift more? Never adjusted valves on these newer motors. Is the valvetrain not adjustable? Seems like .025 (that's a quarter of a tenth of an inch) would be eaten up by being just a dab more preload on the hydraulic lifters....thus adding little or no additional lift. Even if it did, it would only be about .04" additional valve lift. I know on Gen I and II smallblocks, different length pushrods do little more than correct valvetrain geometry. Somebody educate me. It's early and I've yet to learn anything new today.