I have a 2005 Silverado ext cab 1500 with a "T" code LM7 5.3l. I want to do some performance upgrades to it but am limited on cash. I primarily want to bump the CR, and was thinking about pulling the heads and having them milled .020 which from what I've read would put it in the 10.5-11:1 range. I'm new to all this and not sure what all that would entail and can't for the life of me remember which page I found a ton of helpful info on. I'm not sure which heads my truck has on it from the factory but I found a set of 706's at a local salvage yard for $200. Open to all suggestions, thanks.

Current mods include:
Spectre CAI
Hypertech Power Programmer (dynotune planned for the future)
4.56 gears
previous owner switched rearends for towing purposes(unsure of identification of the rearend just know the cover says Mag-Hytech)
35" AT tires
Dual flowmasters w/ dual cats(off factory exhaust manifolds)
4L60e transmission
Limited Slip Differential

 

Lots of performance mods to do before resorting to milling the heads. Besides, milling 5.3 heads .020" would result in about 9.8 CR not 10.5-11 like you mentioned.

 

What is your budget? Get some long tube headers, free flowing exhaust, and a custom tune. This will cost around $1000 and will really wake it up!

 

What all would I need to do before milling the heads? I was going to get the heads to start with since I found a set for $200 (sounded like a good price to me) and then wait til I had a cam before installing them. I already contacted BlackBear about getting a AutoCal tune from him, still awaiting reply. If I did the LT headers would those eliminate the cats? (sorry, new to the performance world) Budget is about $1500 right now. Thanks again.

 

U can do LT with or without cats. You would need to order a set with cats if u want them for emissions.

Get a good tune and should make a noticeable bump in power.

 

I agree, longtube headers would be a simple easy performance increase. Check out our stainless truck headers and new stainless ory.

1999-11 Truck Headers & Y-Pipes