Distance Between Block & Flexplate?

[66FAIRLANE]

So tonight I was doing a bit of prep work on a std bore 390 block before taking it to the machine shop. There were only three press in plugs in the oil galleries at the back & 4th hole was empty but had a thread. No worries I thought I will just use a screw in pipe plug & maybe even tap the others. Upon clean up the thread looked a little coarse. Yep, 1/2"NC. Yes I can make a headless type pipe plug from a bolt but I thought I might just use a bolt, leave the hex head on, put a copper washer under it & Loctite it in. Will a bolt head back there interfere with the flexplate?

[Falcon67]

I assume FEs are like the other Fords in that there is a block plate the goes on the back of the engine before the flex plate or flywheel is installed.  So I would make sure that anything used does not project past the back machined surface of the block where the bell housing attaches.  I'd use a straight edge to verify. 

[67428GT500]

No galley plugs are 1/8 NC. They're 1/4 NPT.  My plugs extend past the bell housing mount. There are four holes where the pipe plugs are that encircle the cam plug in the rear on the plate.They protrude about 1/8" past the casting.

                                                                                   -Keith

[66FAIRLANE]

I have seen some engine plates with holes to cater for slightly protruding plugs & others without. Mine doesn't have them but nothing a hole saw won't fix. Is there room for a bolt head though? Or should I just make a pipe plug in 1/2"NC? I sort of like the idea of a bolt head with copper washer.

[Ranch]

I would think that if you had welsh plugs, everything would have welsh plugs.  That is unless it’s a ‘61’ HP 390 with the oil pressure relief valve just under the center main galley at the rear which take a special fine threaded straight plug, but I believe that was a solid lifter block.  I don’t know if early FEs had a block plate, I was thinking the plate came along with the new flywheel and starter configuration but don’t hold me to it.
Which hole did you find the threads?

[66FAIRLANE]

I would think that if you had welsh plugs, everything would have welsh plugs.

Somebody previous to me has done this. It's not factory.

[Falcon67]

No galley plugs are 1/8 NC. They're 1/4 NPT.  My plugs extend past the bell housing mount. There are four holes where the pipe plugs are that encircle the cam plug in the rear on the plate.They protrude about 1/8" past the casting.

                                                                                   -Keith

Interesting - would not expect that.  All the 351Cs I build and even tapping and plugging on a 302,none even get that close to the block plate.  They are nearly flush with the raised boss on the rear of the block.  If something stuck out so far it needed a hole in the block plate, I'd be working on reducing the height. 

[67428GT500]

The block plate has holes from Ford. Most FE plates do.  If you tap them deep enough to be flush you actually restrict oil flow to the #5 main.  Strangely enough the block I have was all pipe plugs except the one behind the distributor. I drilled and tapped that one.   
                                                                                 -Keith