75 Series Ute

If its a 1hz motor it would be best to simply replace.

You can buy new out of the toyota box, genuine factory for between $8-10K if you look around.

They came with 4 engines so you need to tell us which one.
I had my 1HZ rebuilt 2 years ago and it cost me $5k for a long 1HZ motor. I had to remove the engine and strip it of all the outside parts,sensors and plugs and replace them.
You could add another $2k+ if you have to pay someone from start to finish.

If you have to pay someone to do everything,its best to have all the reconditioning and installation done by the same shop.

There is also a list of small items like water pumps,oil,filters,coolant,hoses,timing belt and a few large items like radiator,clutch fuel pump and injectors to think about.
The manifolds and flywheel also may need machining.

You can leave some of these items out but if you have to go back and do them in 6 months with the engine in,it will cost much more.