Stabbing a JDM or buy core to rebuild, what is better 3.4L? Plus any 'updates' that should be done?

I'm fast approaching 300k on my 2002 3.4L Tacoma; like in the next couple days. It never felt like it had a lot of power especially when compared to 4.3L S10 in similar trim(seat of pants difference) Similar trim is 31" tires with 4.1 gears. I've got a hill on my daily drive that I have to drop a gear(4 to 3) to maintain speed(55mph) in the Tacoma while the S10 powers through fine.

I bought truck at 200k so I have no idea of maint before that point. My maint hasn't been great but not horrible.

I'm looking at getting valves adjusted in the near future in hopes that takes care of power issue. I haven't checked compression but should be able to do so in next few days. Zero tools to do leak down test.

In hopes of minimizing downtime, I want something in hand ready for a shop to stab in. I'm considering doing a JDM or buying a core to get fully rebuilt. It is NOT an option to rebuild engine that is currently in truck... nor is it option to buy JDM to do full rebuild.

I've heard good and bad about JDMs. But I do have a dealer down the hill from me in Sacramento so it is tempting. I would probably replace timing belt and do an external 'seal' job.

I've heard some horror stories about rebuilding the engines even when using OEM parts. But I've got Rancho Cordova junkyard row also down the hill. Still over an hour to go get.

So what is the best approach. My intent is to keep the truck until the interior completely falls apart so fully bullet proofing drivetrain is money well spent in my mind.

Somewhat related, what are general MUST do internal upgrades before installing the engine?

Slightly less related, what are MUST do internal upgrades for potentially going super charger a year after engine replacement? I've heard with turbos of opening up the ring gap. Is it needed for super charger? I can't go too wild on the super charger power bump due to Calif smog stuff

 

Having done a few 3.4 JDM motors… they are not “drop ins”. The pulleys have to be taken off your engine and put on the replacement one, the rib count on the serpentine belt is different. If yours has an oil cooler and the replacement does not, you will have to swap over the cooler and relocate the oil filter housing and put a water pump on that has the coolant port for the coolant hoses that go to the oil cooler. The oil pan and your old oil pickup will need to be swapped too. I would use this as an opportunity to check the rod and main bearings.

 

Long block usually doesn't include anything beyond assemble block/heads... no accessories, pan, intake, exhaust, etc. The expectation is swapping everything over from old engine.

From your last comment, it sounds like it almost isn't worth paying the premium to go JDM if I need to starting pulling it apart.

 

I still prefer to go used lower mileage if possible. Getting harder and more expensive these days though.

I've seen quite a few rebuilds fail shortly after install. Cheap Chinese rebuild kits, coupled with shops slamming out the rebuild as fast as possible. Rebuild shop blames the installer, or blames the veh owner for not replacing every external part.

Toyota assembled these engines better than anyone could today.

 

From my experience with Subarus
JDM engines are great option
IF
You are a wiring guru

same engine WAY different electrical

Can’t speak for Toyotas
I would definitely press vendor for what exactly needed unless plug and play

 

I have a remanned from sunwest auto with a few thousand miles on it and it’s running fantastic. Cost for the engine was $3600 after core return. Pretty happy with it so far and they are great to work with. It will take some time but I will update my review on it later down the road.