Hi everyone I would like to no iff (sorry my english is bad am french Québec ) a 4.2 votec trailblazer engine would fit in a H3 because i want to buy an H3 but i no the engine is not enought powerfull for the weight of the truck and i dont want the model whit the 5.3 vortec anybodys no if is possible?

 

Anything is possible but it wouldn't be an easy or cheap swap. While they are based of the same block, the I5 was selected over the I6 because of length. If you feel the 3.5 or 3.7L is to underpowered, why don't you want an Alpha (5.3L V8)?

 

In English Michigan. The I5 is not under powered! Plenty of low end torque.

You can do a few simple mods for more and be $1000s ahead of an engine swap.
Get an intake, PCM tune, CAT back exhaust (optional), Efan conversion and TB port/polish.

I6s will NOT fit an H3.

 

i would suggest that you test drive an i5 h3

 

What about the new +300 bhp, 3.6 V6 from the Camaro with a 6-speed auto? That would be a nice swap!

In the meantime, the I5 is fine for me too.

 

because I arely try the colorado whit the 3.5 and the 3.7 is enought powerfull and relly good on a pick up because the weight but the H3 quote little bit heavyer then the colorado but like Doc Olds said mayby buy one and put some mods in it like that i would have little bit more whit it and more easyer to do the mecanic it because the it small , I have an S10 ZR2 whit the 4.3 vortec and is tide when i do the mecanic in it

 

You got to keep in mind the H3 has a different gear ratio then the Colorado also. The 3.5 and 3.7L isn't that bad, even with 35's IMHO.

 

i would suggest that you testdrive an i5 h3!!

 

I purchased a 2004 Trailblazer 5.3L and plan to put that engine and the 4x4 (part-time) transmission and front end in my 2007 H3. I also plan to convert the gears from 456 to 410. I bought a computer (ECM) and harness out of a 2009 Alpha.

Does anybody have any input on this?

 

Trailblazer has the same 8 point rear end gears as the Hummer or Colorado. Hummer is 456 gears and the Colorado is 410, with a part-time rear end. The Coloraro 3rd member/differential is the same width and same type as the Hummer. The half shafts pop in so basically you can put a Colorado transfer case in that's not full-time with some diodes and limit switches on the high four and low four. You can activate the front end of the Colorado underneath your Hummer and with the 5.3 I feel I ought to get better mileage and a lot more torque than with the 3.7. Basically an '06-'07 Trailblazer engine, transmission, computer and transfer case will fit directly in. You will need to send the wiring harness and computers to Current Performance to modify the wiring and re-flash the computers.