Is it necessary to block of all the nipples on the LIM (Lower intake manifold)? I am gonna bolt my rails in tomorrow and don't want to have to pull them again. I am running a single turbo.

And where can I get caps for them.

 

i was mislead by the title

 

All nipples have to be used or blocked off. If you do not you will have low Vac which could cause crappy idle and over all poor running conditions. You can find caps at any auto store.

 

Not necessarily, he did say LIM, and there are 4 of them between the front and second runner that are simply passageways through the manifold.
If I remember correctly there are like 2 or 3 on the LIM that do need to be pluged though.
Make sure you find a rubber plug as opposed to the shinny urethane ones they sell. They don’t seem to take the heat very well and will pop off easily. They sell packages of rubber ones in a variety pack, or you can get them out of a bulk bin sometimes. Some people zip tie the smaller ones and use a crimp lock hose clamp for the larger ones for a little extra safety and piece of mind they wont come off.