I have the vaccume tree hooked up to two cylinders but your right its not enugh vaccume.

But this can be over come by manualising the valve body meaining there will be no need for the vaccume modulator.

So if I pull the pan off the tranny and pull the valve body out will an auto place be able to modify it for me (to save on labour costs) or will i have to take the whole car down??

You will need to remove the modualtor & block off the govenor circuit. There is also mods to do in the valve body. leave it to the pros. Because you now have a minifold tube per cylinder you can only take vacume from 1 cylinder so thats probably not enough. if you can some how get vacume from all cylinders it might make a differance. Thats the only logical explanation i can think of. Something i did on a turbo 400 in a ferari once was put a restrictor in the vacume hose because it was getting too much vacume. There is heaps of other things it could be if you want any help PM me.

There is not enough vaccume because of the dellortos, causing it not to shift properly yes a more sensative vaccume modulator would work but I read all i can find about the jatco a12 auto and even if i put a more sensative modulator on its still not going to shift when I want, so Im going to manualize it.

Does anyone on here know how to?

there is a vacuum line that runs from the intake manifold to the vacuum modulator on the rear of the trans, if you disconnected it, or it has a hole in it the trans won't shift.
figure out why it isn't hooked up, rehook it up and it should shift much better.
most RWD Nissan transmissions are very similar to Ford's C4 trans, both in construction and operation. any good trans guy should be able to advise you further.

Since i put a dellorto on my a12 + auto it wont change to third till like 80-90 k's so im stuck in 2nd till there is no one in front of me causing bad economy. I dont want to spend too much money to fix the problem as im planing to put my SR in as soon as i can afford it.

Can you just buy manual valve bodies or is it like a custom thing?

Can u do it without removing the box?