what engine does a 1999 5.3 l chevy silverado have
 

I'm getting conflicting information. Can anyone tell me for sure what engine my 1999 (new body style) Silverado has? I do know it's a 5.3 L.
Thanks

so you have a 5.3 Liter LS Series V8 engine. you kind of answered your own question. what else did you need to know?

5.3L 323ci LM7 Iron block with 9.5:1 compression Gen III motor

So, is an LM7 engine also a LS series engine? Are parts on all LS engines pretty much compatible?

More questions
 

My throttle body has always been sticky, it is a known problem with my truck, and I am wanting to put in a new one. I'm thinking it will give a little more umph without hurting my mileage. I'm seeing 80mm, 85mm, 92mm and 100mm throttle bodies. My bet is that bumping up the size will help but the bigger sizes are a waste of money. What do you guys say? Also a spacer is a consideration but a local guy tells me it's just a way to seperate me from my $. Any ideas on that?
Thanks, -Mugs

Yeah its a LSX motor or LS based motor. The truck motors have great heads with plenty of flow so I would leave those alone. I have taken a stock cam out of a 99 T/A LS1 motor and put in my 2001 and gave me bout 15 hp to the wheels. So yeah everything except for the bottom or crank rods and pistons. The intake will fit but some grinding has to be done.

Bigger throttle body does help but it wont do no good when the computer isn't tuned. It will sense more incoming air and add more fuel to compensate, then you will be running rich. Jus take some tools and bore out your throttle body. Real easy and helps alot with throttle response.