Help I need some reliable info.

I'm hoping you guys can solve my problem. I have a 2000 Chevy S10 Blazer 4dr with 4x4 and a 4.3L V6. The motor has over a 175,000 miles on it and it is starting to show it's age. I am leaning towards the newer LS family. Getting the motor is not the problem due to friends and friends of friends who happen to own salvage yards.
  Since the Blazer is my daily driver, I wanted to know a few things before I tear into it and spend my money only to had a nice flower pot in front of my house. I asked around on some of the V8 S10 websites and all they did was "make a guess" on my questions. Since most of you guys in here live and breath this stuff, maybe I'll try here.
  First question is about the motor. Should I go with a 4.8 or a 5.3. The motors will be coming out of trucks or SUVs. I was also told that some of the motors are made of aluminum and weigh the same as the 4.3.
  Question two, will the LS motors bolt up to the trans or do I need an adapter plate for it. And question three, can the trans and transfer case handle the power and torque of these motors. The trans was redone last summer and the transfer case is getting redone when the motor is out of the Blazer. I will apreciate all the help you can give me.
  Guy 383  

before you think about swaps....

i have seen a lot of 4.3s go a lot farther than that...

tune up....  plugs... wires... cap... rotor... coil....

was the intake manifold gaskets changed yet??? water pump and thermostat???

these are normal wear items on 4.3 motors with close to 200K on them.

the distributer caps and rotors really effect how it runs...  the carbon center button sheds carbon and causes misfiring..       the ignition coils tend to leak high voltage through the sides of the center winding.. look at it... search for white dots or circular dust patterns between the core and the laminations...


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i am not saying not to swap in one of the available V8's...    but for a daily driver... that needs a motor..  it is far faster and easier to swap in the exact motor you need... that way it plugs in... no modifications are needed... drivability remains... no computer tuning is needed...