Can anyone tell me the stock pushrod length and size??every parts store I called is giving me a different length...anywhere from a 7.138 to a 8.103 or sumtin...I thought the length has to be exactly 7.4??? and I dont know what diameter..

(LS1 Stock Pushrods)

 

7.400 Length, 5/16 Diameter

 

what he said....

 

Isnt the stock length more like 7.385 and not 7.400 or something like that? Less lifter preload from what i understand.

 

Yes, stock is shorter than 7.400". Most use a 7.400" when going to an aftermarket camshaft because of the smaller base circle...smaller base circles need a little extra length on the pushrods.

 

Yeah i had to run 7.450s for my cam because of the smaller base circle. Didnt the Ls6 cam have a larger base circle too with like 7.350 pushrods? Off topic i know just trying to learn haha.

 

Stock is 7.380 gauge length what all the documentation ive read. I dont have a way to measure gauge length, but they mic out to 7.396 total length. Figure most pushrods go by gauge length, so theyre about .020 shorter than standard 7.400 aftermarket pushrods.

 

Rough coversion with 0.100" diameter hole is

Gauge Length = Overall Length - 0.017"

so your numbers come out OK. I have measured then at 7.385" gauge length.

 

can we get actual proof from GM of the size...

7.380 or 7.400

 

I have measured a few times and come up with 7.385". Not sure 0.015" is that big a difference unless you are using lifters that have a tight tolerance on preload like Comp R.

 

It's a good idea to get a pushrod checker to determine what pushrod you need. It seems like every setup is a little different.

 

So what length pushrods do I need? Lr4 4.8L V8 swapped in a 2006 GTO LS2 cam


stock base circle 1.552" measured (Gm spec 1.552")

Ls2 cam circle 1.525" measured (Gm spec 1.520")

Stock rods 7.380" (I guess even though they call them 7.4") ???

1.552-1.525 = 0.027

1.552-1.520 = 0.032

7.380+0.027= 7.407

7.380+0.032= 7.412

so I need rods between 7.407 and 7.412 ?? WTF were do I find those and is my math right? I'm thinking either 7.4" or 7.425" someone said 7.45"but won't that bottom out my lifters?

Were can I find true 7.4", and not this pseudo "7.380" that everyone calls 7.4"so confusing!


Also what is gauge measure for length? never heard of that before?

 

Jut read you need to divide by 2? Is that because of the diameter verses radi?

so then it would be

0.027/2 = 0.0135 + 7.380= 7.3935
0.032/2= 0.016 + 7.380 = 7.396

Looks like 7.4" push rods are in order??

But why does rock auto list new stock push rods as 7.3180" must be a miss print? They say it on every LS based motor I can find?

 

Are you an engineer?