I have a 2001 Blazer with the 4.3l. The engine has a knock, so I was considering an upgrade to a V8, maybe a 5.3l or 5.7l.

questions:
1. will a V8 fit without major modifications.
2. will the wiring match up or can I get a harness that will make everything work like original.
3. would I need the computer from the V8 donor vehicle.
4. would I need to upgrade tranny or transfer case.

any input will be greatly appreciated and useful.
Also, if there is already a thread about this, I appologize, but I couldn't find one, thanks.

 

Check here

 

I'm thinking the same. But i've checked all over JTR and can't find anything about 5.3s...

 

Installing a 5.3: https://blazerforum.com/forum/builds-48/2002-xtreme-v8-ls-swap-34022/