I checked the PHRF rating for a 356 and it comes in around 145. The 183 rating you are showing is totally unrealistic in my opinion. PHRF ratings are always given in 'race ready' condition. This means a 150-155 headsail, folding/feathering prop, empty tankage and a standard spinnaker setup. Some fleets will give a separate rating for JAM (jib and main) but those ratings wont vary too much from the normal rating. The important factor in ratings is not the total number but the difference between ratings numbers of different boats.
BTW I made HUGE error in the Portsmouth rating of the 35.5. It is rated 76.8 not the 93.7 I first reported. Sorry for the error, I was trying to remember the number but CRS sometimes raises its ugly head. You can convert PHRF to Portsmouth using the formula :
DPN = (PHRF/6) + 55
This would yield a DPN number of 79.2 for the 356 with a PHRF of 145
PS, no the 35.5 is not a B&R rig, but the 356 certainly does have one.