So my thought right now is to buy a truck and drive it while I'm building up a secondary motor in the garage and when the first motor goes or I've built the motor by then I will have one to install

The years I'm aiming for the truck I'm buying is the 1999-2003 timeframe. And I've heard a lot of people recommend the 5.3 motor for overall performance. When I search for a used / junkyard block is there a certain block that I want as far as GM code or are they all pretty much the same. I know with the old 350s depending on if car or truck it was a 2 bolt main vs 4 bolt main, or that some blocks from Mexico were prefered for their high nickel content. Of course I would like to get the $200 block everyone talks about but I don't want to buy the wrong block and have my time effort and money wasted. I know aftermarket blocks exist but I would like to keep the purchase price in the 2-300 range with a 5-600 max

 

Think there all the same cylinder heads are the only difference, just make sure it's gen III not IV

 

What's the difference / how can I tell the difference between the gen 3 and gen 4 ?

 

Easiest way to tell, is gen 3 has knock sensors in the intake valley. Gen 4 has them down by the engine mounts.

 

GenIV also has cam sensor in timing cover. Most all junkyard motors will be genIII genIV is like 08 and newer? Correct me if I'm wrong on year

 

You're wrong.

The Gen 4 engines started in 05 but didn't get swapped into the trucks until the body style change in 2007.

Stay away from FWD car engines as they are not the same either.

4.8 and 5.3 use the same block. So keep an eye out for someone discarding a 4.8 block as you might find someone that does not know the difference and just wants to get rid of it.

 

Are there block numbers I need to look for to see which is which size or how can you tell otherwise

 

Id go with a LM7 anyday for boost!

 

How much power are you trying to make?

 

As its my first time , I would say. 5-650 would be respectable , but 650-800 would be icing on the cake.