Original engine or not

My 2000 taco has 375,000 miles. I purchased used 2024 and it runs great! Compression 180 all cylinders. No leaks, etc. I’d like to know if engine is original or has been changed. What is best way to determine this? Thanks to all.

 

Well, I'd hope a used '24 would still have the original engine.

 

Not really any definitive way to tell but a reman or salvage engine will almost always have heat tabs stuck somewhere on the heads and/or block, if those are present then you know it's been replaced at some point in it's life. Otherwise unless there are service records of it who knows but it's not uncommon for these to go 200-500k on the original engine if it's well maintained.

They look like the back of a shotgun shell and the center will melt out if the engine is severely overheated.

 

A thousand pardons! My year model of Taco is 2000 prerunner, not 2024 also, my engine number, taken from block on lower drivers side is
3RZ. 2136695. This number is stamped into block with 3RZ in large block letters preceeding the other numbers. Just trying to determine if engine is original.