I have a 2005 Avalanche z71 with L59 5.3l flex fuel engine and I do a good bit of heavy towing with it and would like do a cam swap that'll help toque in the 1800-3500 rpm range to complement the other mods the truck has so far.

So far I've installed 4.10 gears, 33" all terrains on 18"x9" billet wheels, torsion keys up front, k&n air filter in the factory high flow air box, flowmaster super 40 muffler in the factory 2-7/8" od exhaust, sux trans cooler, all aluminum radiator, engine oil cooler, 1000lb air lift in coil air springs, and full custom tune using my hp tuners setup. The truck runs around 2900 in 3rd and around 2200rpms@70mph in od.

Any suggestions or recommendations?

 

Do you want to keep the stock converter?

If you do something in the 212/218 cam size or very similar should get a good amount of HP and torque through the mid range there.

 

212/218 Low Lift ( 550/550 ) on a 112 LSA

 

Yes I would certainly want to keep the stock converter, I'm not looking to do anything transmission wise until it's time for a rebuild then it'll get the full treatment I give all 4l60es I build. thanks for the responses on the cam selection.

 

Just thought of another question as well would I be if it any by installing a set of corvette 243 casting heads I have at my shop on my 5.3 in my Avalanche? I know the chambers a little larger and would loose a little compression installing them.

 

4.56 gears would have been much better.

 

Putting stock 243 heads on the motor would lower the compression ratio unless you milled them. Most guys mill the 243/799 heads about 30 thou to get back to factory compression. The 212/218 will clear no problem with the milled heads.

-Avery

 

Bumping the compression will help with lowend torque. A larger cam will not gain you any Torque below around 2400 RPM. Your stock cam will provide the best lowend torque. A Comp 212/218 lowlift cam will start start showing gains around 2400 Rpm.