i usually go about doing this with a cigar through the brake booster to intake manifold but im not seeing a vacuum? is there another port that i could do this through?

 

Ok, some cats do have a blanked off port, others no not. If you look closely towards the front (of car) end of the intake manifold there might be a little rubber stopper sticking up the appears to go nowhere. This was left in situ from previous models that had vacuum assisted brakes. If you don't have this port, then you can of course install one yourself if you are going to continuously need one for servicing with one of the many available snake oils.....

Because these jags have a separate hydraulic brake boost system there is no vacuum booster, hence no vacuum line (just the little take off as above). You can, if you so choose, remove this system and install a vacuum assisted one in the future if you start to experience brake system problems as it's a more cost effective repair. Note though that it's only available for autos. If you have a manual then there is not enough clearance to mount a vacuum booster without extensive modifications

 

I should have also added before I went off on a different tangent... there is of course a air intake regulator half way along the intake manifold that you can plug into to do a vacuum test... again, refer to chapter 6 in the haynes manual