Block drain/valve kit...

Did the part numbers you stated fit? I have a 92 351 Ford PCM direct drive and my block drain plugs are 1/4" MNPT. so i bought:

5 Each 4921K2, Drain-handle Brass Stop Cock Removable Handle, Internal Seal, 1/4" Npt Male.

Then for the manifolds: 2 Each 4429K423, Low-pressure Brass Threaded Pipe Fitting 3/4" Male X 1/4" Fem Pipe Sz, Hex Reducing Bushing.

I hate NPT I always get confused cause the 1/4" MNPT measures more like 3/8" diameter.

The PO had changed one drain to a bushing with the square plug, then rounded it off....one of the manifold plugs was rounded too. You could tell he used a 1/2" drive ratchet. The spring loaded ball on the drive did not allow for complete seating and then the ratchet slipped and buggered up the square hole. Someone had used vise-grips on the threads once too.

Where do you get the handle/stem drain cocks for the PCM 351? I know mine are getting on their last legs and would like to get these valves to drain.     

Pete,
My piont is at sometime the block will have to be probed with a wire to remove some scale. It's not everytime the valve is opened or even once a year or 5 years. The openings on my ball valves are bigger than the openings on the petcocks.
I like the ones I have because they direct the flow of water into the bildge with a short peice of hose. When I've used petcocks I use a peice of sheet metal to direct the water so it doesn't get all over (the carpet, exhaust ect...)

They both work.       

LKG_ wrote: The manifolds are 3/4" NPT if I remember correctly. As far as I can tell, the only brass reducers they have that will mate up with their stopcocks are 3/4" to 1/4".

I sure can't remember all the stuff that Mcmaster has so I looked it up! Plenty of brass hex reducing bushings at McMaster!
Enter their part # 4429k418 It's a 3/4" by 3/8"

Double check the block drains. I don't feel they are 3/8". Keep in mind that pipe size goes roughly by the ID and not the OD.

From the other thread I linked:

8122pbrainard wrote: Keep in mind that pipe sizes can be confusing. The OD of 1/8" is roughly .400", 1/4" roughly .540" and then at the manifolds, 1/2" .840" and if 3/4" 1.050"

3/8" will be .675"

Waterdog wrote: Pete, I'll open 1 drain at a time and if the flow is down then I'll take the pipe fitting out and probe the hole with .040 safety wire. The samething you do with a pipe plug. "If it's not stopped up with rust, it will be."

Andy,
If you need to remove the fitting or valve, what's the point of putting in quick drains?

I suggest using the removeable valve stem stopcocks that I've mentioned in other threads. The last time I mention them was in this thread

Here's the picture again. I've got them on all my boats.

What ever means of draining is used, being able to probe the drain hole with a piece of wire is of utmost importance.

You may also want to do some searching/reading here on site. There's quite allot of info on the subject - recent too.

I put one together a few years ago at the local hardware store, it ended up saving me only the shipping cost from SKIDIM. Just take your plugs with you to the hardware store after you drain everything. It was handy, but I don't use that anymore, there are too many things to drain now that it won't get. (V Drive, transmission cooler, strainer, heater) There is enough room in the Excel to keep a small marine heater on a thermostat, and I drain it by hand if it looks like we are going to get into a long cold period, just for peace of mind.