Im in the "hey that would be cool" stage of a mild 1200 buildup. At this point I have more enthusiasm than practical experience. This is what im kinda of thinking of doing; A12 block bored 30 over, gapless rings, low end to mid range cam, a little port and polish work on head, A14 intake (does that bolt right up to A12 block?), header, and whatever else my budget and skill alows during the course of this learning experience. Any thoughts?

a14 inlet wont work, stud holes are diffrent and its likely to have oval inlets as opposed to the round of the a-12

otherwise sounds good,
but why not use an entire a-14/15??

Welcome to the club Animal

Sounds like you are taking the sensible approach with a good simple plan and not going into the whole " bigger is better " category - MUCH RESPECT

Yeah that sounds like a good basis for a good strong little motor. There is PLENTY of info here on the site that you will find invaluable just use the search box on the left as this topic has been discussed heaps so you'll get some good ideas

Just work out your budget, what the cars purpose will be, driveabilty and how much work you can carry out yourself but above all.........
HAVE FUN

Animal
Welcome aboard. You will find that there many things that you can do with the little "A" series engines, & if you are using the original early A12 block, you can use bore sizes all the way out to 77mm which is a big increase when expressed as a percentage of the original 73mm.

I don't think that Nissan make .030" OS pistons, but perhaps someone else does. As far as i know, the stock oversizes are .5, 1 & 1.5mm. The A12a engine is 75mm, so if you have an early engine, then finding a junk A12a shortblock will give you some bigger bore rod & piston assemblies at low cost [the wrist pin is bigger, so keep the rods with the pistons]

The A14 head will fit all blocks, but you need to modify the oil feed to the rockers if using it on an early block. I think that the compression will drop a little with this head on an A12 also, but thats what head mills are for.

So many choices to make, so much fun to have.
Chris