I am swapping my 850s over to the primary. I have a question regarding the o-rings and insulators. A while back I purchased a whole new set of o-rings and insulators from Mazda, and the 550's and 850's are slighly different. When putting the 850s in the stock rail, what o-rings do you use...

is there a write up on this swap?

 

The o-rings are for each injector. Just put the new rings on the 850's and put them in the primary rail. I'm sure you know that the rail needs to be milled 1/8" or .125". LMK if you need any other info...