whitch is the better motor to swap into my02 silv z71. i know the motor should be from a 05. is the silverado ss good motor and what is it lq4 or lq9. what about 2500 pickups is that the same motor rated at 350hp or the escalade motor rated at 350hp. witch is the best what year and from what model. thanks.

 

lq9 is the better motor. The SS and cadillac AWD are LQ9. The 2500s are rated at 305 or lq4s.

 

For 2005 the only difference is the flat top pistons of the LQ9 vs dished on the LQ4. Depends on what your goals are for it. LQ9s usually cost a fair bit more than LQ4s.

 

They are basically the same except for the pistons which increases the cr to (10.5 ?). Someone add to this or corret me if I'm wrong.

 

From 05+ that is correct, but the 01-04 LQ4 rods are not as strong as the LQ9 rods, or 05+ LQ4 rods. 99-00 LQ4's had iron heads and a longer crank that will not bolt up to a 4L60E, so most guys avoid those.

 

so im looking for an lq9 out of something 2005 or newer and silv ss or escalade. the motors in the ss and escalade make 350 hp. im planning to buy a used scrap yard and rebuild. there will be a stamping on the block somewhare. ehare is the stamping. and do the lq9 have aluminum heads. the lq9 willl bolt into my 02 silverado z71.

 

Saying that flat-out isn't necessarily true. Before '05, yes, the LQ9 had better connecting rods, but most people will never make enough power to break the weaker rods in the pre-2005 LQ4.

After 2004, it's basically a draw. Yes, the LQ9 has an extral half-point of compression, but most of the horsepower difference from the factory has to do with tuning.

The LQ4 was rated as high as 335 hp in the Denalis, so the power difference is marginal.

To the OP, buy which ever you can get the better deal on.

 

Just buy an 05+. If youre going to rebuild it, its all a moot point, unless youre keeping the stock pistons. If so, IMO, the LQ9 isnt worth the extra price you pay over a LQ4. The only difference is the LQ9 has flat tops and the LQ4 is dished.

 

If your buying a converter anyway, you can get a 99-00 LQ4 cheap cause nobody thinks they will work. Just tell your converter guy what you have and he can make a converter to work with longer crank at no additional charge. I have a 2000 LQ4 with a Yank ProTruck 3600. I bought my short block brand new for $300. I installed ARP hardware, made flycuts, and put my 243's on it. That gives me more piston to valve clearance and more compression then an LQ9...

 

x2!!!!!!!!!!