No harm intended my friend.

 

thanks for the info

 

first off there were two different lq4 horsepower ratings the first couple of years they came with cast iron heads they were rated at 300 give or take a few then they came with the aluminum 317's which were rated from 320 to 325 depends on where you look the lq9's on most sites say 340 to 345 now that is rated horsepower not with custom tunes i have an ls1 book that dynos an lq4 with full factory exhaust and factory airbox i think a factory tune made 337 flywheel

 

Don't quote me on this, but the 99-00 shared the same camshaft as the 4.8 and 5.3 which was a 190/191. I know for a fact that the LQ9 uses a 196/207 cam and has orange LS6 style springs. I would bet that the 01+ LQ4 also uses the 196/207 cam.

 

Here it is:

'99-'00 - 191/190 .457/.466 114lsa
'01-'06 - 196/207 .467/.479 116lsa


Also, the only reason some LQ4s were rated @ 300 HP was because it was only rated at 4400 rpm. On my stock LQ9 dyno, power peaked at 5200, and there was a 20rwhp gain from 4400rpm to 5200 rpm. So that right there is the majority of the rated difference between the LQ4 and LQ9, which is negligible.

 

even a 05 LQ4 was rated at 300 in a 1500HD. it just depended on the application.

 

so is the only diff. the cam and if I plan on changing the cam it doesn't matter LQ4 or 9

 

All Factory, and flywheel ratings aside. Anyone dyno a stock Lq4 and a Stock Lq9 TO THE WHEELS?

 

and the compression ratio!

 

Sorry guys, I was arguing with my boss on the phone when I replied, yesterday was a bad day at the office!