I have a 99 ext cab z71 with the 5.3 in it. This truck was my daily driver but i am going to be getting another vehicle for that so i can start to upgrade the silverado. I was thinking on rebuilding the stock 5.3 but i want to have more power. Origional motor has 131k on it

For the money, would it be better to rebuild/upgrade my 5.3 or order a 5.7 350 from gm? I am looking to get 400-500hp. I also want to put in a t56, and rebuild the rear end. Is it worth the money to just keep the 5.3 and rebuild/upgrade, or is it better to buy a performance 350 from gm? I want the most bang for the buck.

Also, i live in California. I know that most of the gm blocks a 50 state legal. How would it hookup to the factory wiring harness in my silverado?

 

how bout a 6.0 lq4 or lq9. thats what i'd do.

 

Exactly - get an LQ9 and strap a Radix on it.

 

Or you could just bore out your 5.3 to a 5.7 use a forged piston and have a stronger motor than the alu. block that the ls1 uses. Alittle heavier but stronger block. If you want to take the 5.3 even further, you can make it a stroker 383 by changing the crank and rods. I think I may be going this route when mine goes. I live in Cali as well. I want to go this route because it still would say 4.8/5.3 on the block. so when the smog tech or smog ref looks, he will not know a thing. Now getting it to pass the sniffer test is all in your tune. I seen some really beefed up cars pass the sniffer test, with a detune. Not only for smog reasons, but (chicks) they all say I like it BIG but when it come down to putting it in They are in pain, and it takes for ever. What I mean by this is, big cubes are great, but the chances are that you will need more fuel to run it (depending on tune and set up). And as the fuel prices go up you and me both will be screaming like little B!+@#$ saying that price is too big, and will take for ever forking over the doe! J/K.

 

6.0 would be cheaper, but if you have a z71 4x4 you will not be able to use a t56 because the tail section will not mate to a transfercase. You may want to look at a HD 6 speed. I think it is a zf600 or something like that.