I have just fitted some PEEK seals, after many many attempts to get the brass ones to work. I noticed the PEEK ones were hard to push on to the manifold, and the manifold surface was marred slightly, and out of round by a couple of thou. I managed to dress the manifold surfaces up true.
I inspected the spigot faces closely, and determined that they were OK. Likewise the threads on the spigots and in the nuts.
I smeered some Hermetite Blue on the spigot faces, but I found it smudged everywhere, when trying to align the manifold, and getting the plumbers nuts started on their threads.
I didn't find it neccessay to loosen the cylinder base nuts.
The front plumbers nut done up firm, but the rear one felt a bit mushy.
I made up a fitting for the end of the carb, and put about 5 or 6 PSI air into the intake.
I had very very fine bubbles develope around the gasket between the carb and the manifold, course bubbles from around the rear plumbers nut, and also course bubbles from around a small bolt that screws in to hold the rear spigot in place.
(My other motor has what looks like peened over plugs, holding the spigots)
I tightened the rear nut a bit more, three manifolt bolts, and also the spigot bolt, and viola, no more leaks. Unbelievable.
I found a NOS condensor #1629-30, and put that in, in place of the no brand aftermarket condensor I had in there.
My second hand D16 plugs were not firing, so I fitted a new set, gapped to 30 thou.
I have the M88 carb fitted after the good advise I got recently from the forum, regards the orientation of the fixed jet and stem plug.
I have the low speed out about 2 1/2 turns.
I was able to get the motor to start and run really well, but the starting ritual is still unknown.
I've dicked around with this new restoration project off and on, close on three years, and finally, I have a result.
So, I have a PEEK float, PEEK seals, new float needle and seat, carb rebuilt correctly, good throttle bushes, unmarred maniflold, new plugs and condensor, tappets and ignition timing set as per the manual.
I hope this is a help to some-one.