I have a 4200 vortec engine in my vehicle now that is blown up. Can I change it to the 4.3? Also Will the computer and wiring have to be changed or compatible. What may be some options for me.

 

Colorado based TrailBlazers never came with a 4.3, pretty much nothing would be compatible to my knowledge from motor mounts to wiring, computers, controlling devices and sensors, the whole nines.

 

The 4.2 is an inline 6-cylinder and the 4.3 is a V6, so it's definitely not going to be a direct bolt-in. Even if you could manage to put the 4.3 in the Trailblazer, you would end up with at least 75HP less than you started with, and way worse gas mileage, so it just doesn't really make sense.

 

Thanks for the info. Guess I'll have to look for another 4.2 then. Hard to find I hear? I really don't want to go to a junkyard for one for fear of buying someone else's junk so to speak LOL but I know of nobody selling new crated 4.2 engines for this vehicle I looked on summits racing website and all they have is Mopar engines that are 4.2 with no photographs
Not sure what I'm going to do

 

That 4.2 "mopar' engine is a long used Jeep straight six engine. It came in 4.0 L and the much rarer 4.2L version. It was eventually replaced with a V6. This old 4.0 engine was used in the Wrangler and the Grand Cherokee. Didn't the TrailBlazer come with a Chevy V8---- another rare option. If so, that might be a better engine swap and you would be able to use GM parts for the swap. Don't expect to find one of those in a nearby salvage yard. But it sure would be a nice up grade.

 

GM had their own Inline 6 but i think it really only shipped on Colorado-based Trailblazers. best bet would be to just put a 5.7 in it and call it a day.

 

I still say that some of the Trailblazers came from the factory with the 5.3L LS V8. Yes, they are rare and hard to find. But you could possibly find all the hardware and ECM and factory wiring harness to put the GM V8 in it.
Here is a 2008 Chevy Trailblazer 4 door with a 5.3 L 300 HP V8. The you tube host calls it unique.


BTW the Chevy Colorado and the GMC Canyon no longer offer the GM 4.2 L straight six. It has been replaced by a 3.6L V6.