Can anybody tell us how much it would roughly cost to put a new 1400 motor in a datsun ute.

you cant get 'new' a14s anymore i think. a14s bolt into utes without any x-member mods, and if your ute is before 1972 the alternator is on the side of the engine, so some mods are required. a very good condition a14 with all accesories in mint cond is about $500.

then you should think about a different radiator gemini looks good for about $100 and some time and mods.

then theres the usual brake/suspension/ and eventually diff modifications, this vary's too much to give a accurate price. maybe someone can give some advice here?

if you can do most of the work yourself (disconnect wires(and label them!!), rip out the old engine, transport 'new' engine to your house/shop, install engine/radiator, connect wires, fill up with new oils, filters(air, oil fuel), new coolent, radiator hoses etc should cost around $1000 at the ABSOLUTE MOST if you do it yourself

Apart from the cost of the engine ($200ish up) I think if you did the swap yourself it could cost bugger all really, maybe $10.
Stock radiator will be fine , standard ute diff will take all the punishment your A14 will ever be able to give it.

You may need to swap the alternator from one side to the other and get a bit of angle to modify the mounts, but its not anything that would cost any money really.

not much man depends on how much u can do yaself tho.. like save $$ on labour doin it yaself u very mechanical minded? i no a few shire boys like us with a15's in their utes if ya interested..
i got a sr20 tho haha

Fill in tour profile so we know where you are from if you are in melbourne i have a good A15 going cheap