Need a hole/thread size

[RICH MUISE]

If anyone out there in '57 Land has an open engine compartment, could you check a threaded hole size for me? It is on the passenger side inside frame wall, about 2" behind the engine crossmember, and about 3/4" down from the top of the frame. I'm pretty sure it's either 5/16-18, or 5/16-24. I've probably got lots of paint build up in the hole, and I can get both those screws in about 1/2 turn. My guess is it's the fine thread-24 being as it's in a thinner material, but would like to know for sure before I run a tap in there.
It's where the stubby screwdriver is.

[Ford Blue blood]

Rich I believe that hole is for the starter cable clamp and if so it had one of those "pointy nose" 5/16 X 18 cap screws....both the Edsel and the Ranchero have empty holes right now.  The Edsel clamp is on the lower part of the inner fender.

[hiball3985]

Battery cable clamp is on the inner fender on mine also. If no one reply's soon I'll brave the rain and go look at mine. I'm guessing it was one of the self tapping type screws that holds a clamp for a brake line.

[RICH MUISE]

Yep...I'm running the ignition switch wire to the starter and need something to hold the wire away from the exhaust manifold. I felt around the area to see if there was anything there and there was...I just can't tell from topside what it is exactly. I could just run a tap in there, but I don't have room for a tap handle, just the tap and an open end wrench on the square, so the "feel" won't be that good.
Jim...don't get yourself all wet...I've got plenty of other wires to work on.
Thanks

[hiball3985]

There is nothing attached to that hole on mine. Looking at it with a mirror it looks like it has a few threads but I couldn't get a 5/16 18 or 24 tap to start by hand.

I needed to go out and check something for Jay also, I got a little wet so we can blame it on him 

[RICH MUISE]

Thanks for looking, Jim. I looked with a mirror also, and there appeared to be threads, but I never plugged off the holes when I painted the frame..por-15, primer, paint...

[hiball3985]

As thin as the frame is I thinking tapping wouldn't work that well and a self tapping sheet metal screw would work better.

[lalessi1]

Rich,
Mine has a 5/16-24 bolt in it. It appears to be factory original and holds a fuel line clamp. 6 cylinder fuel lines ran down that passenger side I think.

[hiball3985]

Rich,
Mine has a 5/16-24 bolt in it. It appears to be factory original and holds a fuel line clamp. 6 cylinder fuel lines ran down that passenger side I think.

Six cylinder fuel line, that makes sense, mystery solved 

[RICH MUISE]

Thanks guys. Momma wants to go look at furniture...I don't get a whole lot done on weekends!!  I'll hopefully get it tapped/cleaned out when we get back, and before the Broncos game!! Probably correct with the oem being fuel line...5/16 would be a bit large for a brake line clamp.

[lalessi1]

My fuel line is still there and in use. The guy that put the V8 in it crossed the fuel under the engine. The bolt has a recessed head and I don't think it was ever removed until today!

[jumping jack flash]

Just came in from out behind the barn. I have 4 V8  rancheros and a 6 Cyl. sedan out there. The bolt  is for a fuel line retention clip for the six . The V8 is on the other side, same area.

[jumping jack flash]

OOPS! I read about this question this am, and now I see others have already beat me to the punch. OK you have it verified by at least 2 of us who see the fuel line still in place. It is a shouldered 5/16 x 24 self tapping BOLT. That's right, a bolt.You could put a nut on it with the threads it has. Other 's close to it and using the same bolt is the crossover for the front brake lines.

[RICH MUISE]

Wished I had just worked on the car instead of watching the Bronco's game. I did get a tap in there to clean out the threads. Thanks everyone for your help.

[Ecode70D]

I needed to go out and check something for Jay also, I got a little wet so we can blame it on him 

I'm watching you guys.  HAHA