The L33 besides being aluminum, had a little more HP due to use flat top pistons if I recall correctly.

Are you planning to replace the lifters? If yes then I would think AFM/DOD could be less of an issue.

 

Yep,,


Cam/lifters, rocker bushings.
The DOD engines have a different oil pump in them, and a different valley cover.
I usually use a LS6 cover, and a aftermkt pcv.
Additionally, I use a Melling oil pump.
Will also get an LS6 intake.
I may just go w/ the L33. About $2000, free frt.

 

The L33 HP rating was due to it using 799/243 style heads. GM used flat top to get CR back to were they were with the smaller chamber heads. It alsi uses the LS2/LQ9 stye floating rods.

All 2011-14 truck motors are VVT.

The Gen IV LC9 5.3L is same 799/243 heads and has flat tops as the Gen III L33, but has a larger TB on the intake.


To delete the AFM you have to remove the heads if its an AFM motor. You have to change the 8 AFM lifters, AFM lifter tray, and valley cover to a non afm style. Oil pump will work with either fine. AFM is more flow than non unit.

I would do the L33. Same motor as the Gen IV and your swaping to LS6 intake anyway. No AFM or VVT to worry about.

 

Thanks for the input.
The L33 is being ordered.

 

If I might ask, where are you ordering from?

 

Ebay..


Just search for, in my case, Lc9, or L33. [Or, any other engine code, you want].
Many are free frt, 3 to 6 mo's warranty.
We've done this before, and got 1 less than great engine. We called, and they sent another, and told us to keep the first one...
100K on these engines is not a lot of miles.
Make sure you get all the "trimmings", such as harness, ecm, pedal, etc. Buying the accessories ala cart, is expensive.

 

www.car-part.com You can search local yards and call. Use 2000-2006 for Gen III motors and 2007-up for Gen IV. Use either 1500 or 2500hd. RPO code ID's are in the FAQ sticky in a link listing what each code is and year. Tell them you want a complete change over engine with everything and uncut harness.