Throttle Body Install

[FA-18C]

Well, I am in the process of cleaning up a set of throttle bodies for my 70E and began by pulling out the old components. Needless to say this is way more involved than I had anticipated, but so far I have taken my time and am 25% or so done. Started by pulling the aircleaner assembly, then the plug wires, and fuel injection lines. At this point I removed the attachement nut that hold the throttle cross bar, the spring and circlip. Next I disconnected the linkages to make room to access the intake bolts. I removed the stack bolts first, could not seperate them from the bodies, then removed the throttle body-to-engine bolts. I carefully used a craftsman tool retriever (stick with magnet) to get all of the nuts and washers prior to pulling the intake assembly. These came part way out, then I slid out the end of the throttle cross bar and pulled that entire bank. A little careful prying seperated the intakes and throttle bodies. WOW! These throttle bodies were pitted and corroded pretty bad. The replacements look new in comparison. There is play in the bushings and the bore is pitted, correded and extremely nasty. In comparison, the intake valve area is exrremely smooth.

I have cleaned the new bodies, have a decent matching of the butterflies, and have matched the air adjustment screws with 2.5 revolutions from full closure. After cleaning the intakes I will bolt together with new gaskets and replace this bank prior to pulling the other side and repeating.

Questions I have:

1. Can I shoot B-12 into the intake area of the motor to clean them up a bit or will this possible lodge some carbon in the valve areas?
2. Should I go ahead and replace my plugs at this time??

Thanks