Is the base circle of a 04 LS6 cam smaller than that of a stock LS1 cam? If it is smaller, would going to a 7.45 pushrod be advisable? Thanks

 

If you end up needing a set of 7.425 rods I got a new comp set, 5/16 .080 wall thickness im not using, I needed a little shorter for my build

 

In order for the cam to have more lift; it HAS to have a smaller base circle, since the maximum height that the lobe can ever be is just under the cam bearing journal diameter. This is why GM made the LS cam bearings big block chevy sized so the lobes can be wider and get more air in/out
Factory LS6 engines use the standard push rods but the valve tip height is .0236" taller to make up the base circle difference
Also the factory push rods are said to be 7.385' and not TRUE 7.4; so with that being said, I'd suggest a 7.425" length or pull the heads and wack em' .030" for more squeeze plus pop a 7.40" in and be happy

 

I run the 7.425's in my 5.3 with the LS6 cam...works great.

 

Thanks guys. I have two sets of pushrods. Both comp cams. I will put in the 7.40's and check tip contact throughout rotational cycles.

 

The base circle is smaller. As stated the LS6 valves are longer also which compensates some. If I recall the base circle is 0.050 smaller so I would think you would need 0.025 longer if you aren't using LS6 valves.

 

Stock ls1 base circle 19.7mm
01 Ls6 cam 19.3mm
02-04 Ls6 cam 19mm

The 02-04 Ls6 cam is .027" smaller

 

Crap hate it when that happens. Thanks.