Without taking away from the thread, is there a list of items to be phosphated?
So far I have throttle arm, clutch Z bar, hood hinges, water pump pulley ( were all engine pulleys done with this process?), alternator pulley.

David,

Good question...

This will be good to know as I collect L48 engine parts....

I'm a ceramic engineer at my day job and do understand a little about the phosphating process as well as the ceramic coating processes used on headers/exhaust manifolds... Coating like this are quite fascinating.

David.. Here is a great spot to list items.. I'll list what I remember off the top of my head:
Nearly all body bolts ( fenders etc)
Hood hinges
All pulleys but power steering (black paint)
(I have no idea about Air Conditioning pulleys)
The Z bar for clutch
The throttle lever that comes off the firewall
The hood latch ( body side)
The hood clasp base and screw ( spring black paint)
I'm sure more but cannot recall right now

David - see my post elsewhere - Paint and Other finishes..

Nice post Tom. Looks well worth in checking into with the experiment. Finding the correct solution is tough. All the plating places around me have the glitter in the phospate. Steve G. from CA had done a bunch of my stuff a few years ago. No glitter on them. The bad thing with the phosphate plating is, it has the least amount of resistance from protection. Put a lightly coat of oil on them.

I picked up some from the same guy Tom got his from, going to give it a try.

I'm going to try to do it again and this time leave some pieces in longer under a BOIL. Like Duane said and judging from the picture on Ebay.. GM's version has sparkles in it.. Mine and the stuff I paid for does not.. Need to get past that barrier and the choice of oil.. WD40 seems to completly evaporate over time so that will not suffice...

My stuff that I sent to California turned out great. "Detail Plating". I don't think it is particularly sparkly (sp) I do regularly spray WD40 on all of it. It does not last forever, but it also does not cause any adverse effects. I am at three years since the car was finished and it still looks very good. IMO

Gary,you finnaly got out of the snow???LOL,gotta love New York State weather!!!!!
Da weave

Weave, actually we didn't get much snow where I am. It snowed on Saturday about three inches and two hours later it was gone!

Small update: I bought an NOS H2O pulley with a box dated 1973.. The pulley is flagrantly phosphated.. You can see in the picture that they did a shoddy job.. very uneven..and yet NO RUST and lots of sparkle??? Whats the real process that a part can sit for decades in a box that has obviously seen either water or humidity in its life and lasts so well? I don't know yet... No rubbing oil on this piece to keep in nice.. she's bone dry and always has been??? curious
Also.. heard a runor of a factory that phosphates just two towns over.. will be heading that way next week on a recon mission to check it out........
The picture shows the blotchy but unrusted sparkly NOS pulley.. The professionally done ( not sparkly ) but not rusting crank pulley and my alternator pulley that I did a few weeks ago and coated with just WD40.. It is already showing signs of patina

Onward we go

I'm still beating away at this but starting to find out what others ( the pro's) have already realized...The process is difficult to diplicate just like GM !
Rick, you say you have some knowledge of this? Well with regards to the sparkly effect: I went to a local shop that I found that is going to do a sample phosphate job for me. I showed him a Jerry McNeish pulley and the original NOS pulley in the above picture.. He said he does the Jerry process but does not know about the sparkles??? Thinks that maybe theres zinc in the mix as well? He wasn't sure. What do you or anyone else know of this? The Ebay guy I bought my chemical from showed a picture of his getting sparkly so maybe I'm doing it wrong???

Anyhow and update on my original process. Look at the wire stand and notice that it is not rusting..This piece I had in the hot water the entire time I was experimenting. I put the pulley in the solution just for the allotted time of 10-15 minutes.. Obviously leaving it in way longer..like 1/2 hour++ created a thicker better coating. The wire stand has been hanging outside in the cold and wind and rain all this time..The pulley has been in my finished garage and has rusted WAY more...
Some good news.. I had read in my research that phosphate is often times used as a paint primer so I painted the back side of the wire stand with a black spray bomb before I hung it outside and am happy to report that the paint has adhered very very well to the metal.. When I scrape it with a razon blade in resists very well..a very tough paint adhesion... I may wash all my black painted engine bay parts in this stuff beforehand when repaint time comes!

ps.. The little white flecks on the wire stand is residule bondo

Keep us posted Tom. I'm confident you will get it sorted out.

Tom, what's a razon blade??