I'm building up a balls out A12 but have no conrods. just wondering if i can use the rods out of a spare A12A motor i have and put them in a older better A12 motor? i assume they are the same but just wana make sure.

yes you can use the a12a rods same distance center to center, beefier rod and larger pin bore 19mm versues 17mm for standard 1200.
I use the a12a rods in my a12 race motor.
although I am limited to .040" over bore you can bore most a12 blocks to 76mm and use an a14 standard bore piston which is roughly about a 1270cc engine and the bigger bore also
allows better cylinder head flow due to unshrouding of the valves
Bob

If you are going to build a "balls out" engine, you are probably better off starting with the A12a as a base. These came with a 75mm bore to begin with, so pushing it out to 76.5mm would just be the third standard oversize, & 77, or 77.5mm bore sizing would be easily achieved using standard Datsun pistons.

If you want to push it to 1453cc using standard Datsun engine parts, then drop me a line. This should be a doddle in the A12a block, but you will need those A12a rods.