hey anybody, are there any modifications needed when putting 1200 motor into a 1000 ute

The following assumes that you are using a 1200 engine, from a 1200 car.
The engine will fit right in without problems. The later engines need more work, but you did say a 1200 engine.

If you are using the 1000 gearbox you will find the spiggot shaft to be too long. The 1200 crankshaft was not bored as deeply & the 1000 shaft will bottom out in it.
Simply adjust its length with an angle grinder. You will also need to use the 1200 clutch release bearing & you can adapt it to the 1000 bearing carrier, or you can use the 1200 bearing carrier. It's a bit of a fiddle, but it can be used in the 1000 box.

The only other problem is that the stock 1200 engine is taller & the factory air filter housing rubs on the underside of the bonnet, so a sports aircleaner should help.

If you are using the 1200 gearbox, you might need a spacer where the 1200 clutch cable passes through the firewall to take up any excess slack. A small stack of washers should be OK. Use the 1000's gearlever as it was shaped to fit the car & it fits right into the 1200 box.

Another problem is that the 1200's clutch arm will rub on the trans tunnel & you may need to take a ball pein hammer & press it against the area that needs to be massaged. Strike this hammer with a copper faced hammer to massage the area that needs to be moved. DO NOT hit it with a steel hammer if you value your eyes.

You might want to use a 1000 model gearbox rear seal to properly match up with the tailshaft yoke. It's smaller in the skirt & it closely fits over the yoke to help keep dirt out, but the actual seal part is the same for both models.

EDIT
See if you can use the heater fitting from the back of the 1000 head to make hose fitup easier. The hole in the back of the 1200 head is in a slightly diferent place, but it's close enough.
To simplify wiring, use the whole 1000 altenator and mounting bracket. You will need to remove the bracket mounting studs from the 1000 block from memory and I think that one of them is longer, so be sure to refit them in the right order. The way i remember it, the 1200 used equal length bolts. The studs come out easily enough if you double-nut them with the nuts you removed to take the bracket off, so no special tools needed here.

thanks Dats-hot
the motor and gearbox are out of a 1200,
it is a temporary swap as i have another 1200 motor that I will later fit when its ready.