Do the MSD50s have a removable filter? I picked up some bad race gas and after checking the fuel filter and fuel pump filter, they were clogged from this junk in this gas. The fuel pump (external) has a removable filter with a very fine mesh but there is still a concern stuff might have gotten to the injectors.
It won't hurt anything to stick the noses in the cleaner but I would be very careful and not apply 12 volts to the injectors tho some have gotten away with it.
Me, I would probably stick them in and try them out. No big deal to change injectors and it is easier the second time than the first...and faster. If there seems to be a problem, pull them and have them cleaned properly. If you know the owner and you know they are low mileage...stick 'em in and give them a go....that's my advice.
I just installed some used MSD 50's in my car"But I soaked them in WD40 for a couple of months "That time is Not required"But it will help gettin the solinoids working in the injectors if there sticky.Mine runs great so far in the garage!
Keith Davis--86GN,Astroroof,DigDash'TTA crank,Ported polished heads & intake'TRW .30 forged pistons & PT51 Turbo,Manly SS valves,Postons headers,T.C. Orange stripe conv.THDP,SMC alky,Boost command,Scanmaster2,MSD50 inj,Nitto DR's 275/50/15,All the braces,All gauges VDO.