2003 Chevy Trailblazer....how hard is it to pull old motor and drop a 350 in its place I have the Ls model of blazer. Anything helps. I was driving out of town my oil pressure gauge dropped to zero and then started knocking. I hope I didn't throw a rod threw the block but when I pulled over there was no oil under blazer and was not smoking. We are a one faimly vehicle. Can someone help me please

 

If you need this vehicle back on the road quickly, your best option is to get a salvage yard 4.3 and just swap the engine. This can be done in a day and have you back up and running. The 4.3s can be found for $300-$500 at salvage yards around me.

As far as the swap, it is not as simple as just dropping the v8 in place of the v6. you need to have aftermarket engine mounts, electric fans or move the radiator, modify the wiring v8 headers and modify the exhaust to fit.

 

First off, please confirm my suspicion that this is a newer style Trailblazer and not an s-series suv with the trailblazer trim package (even though I'm fairly certain the tb trim went away in 2002).

There are a lot of differences between the two platforms when it comes to v8 swaps. For one, the GMT360 platform actually had a V8 option. Even with a V8 option in the GMT360/370 platform, I still think the general consensus is to find a V8 truck and build from there rather than convert from the inline 6 4.2L given how much needs to change in not only the engine, but the front driveline as well since the front axle goes through the oil pan of the 4.2L I6 engine if 4wd. This brings up another good point...when requesting input on things like this, please list all of the relevant details about your vehicle (engine size, drivetrain configuration, etc) as these details do matter when it comes to determining the best course of action.

I'm moving this the 'Engine & Internal' section as this seems like more a question about the feasibility and process than an actual build chronicle such as the 'Builds' section is meant to contain.