Need help, '68 F-100 360ci.

The left(driver's side) exhaust manifold is cracked. This truck was ordered new with "Ranger" package and all options, so it has the factory

installed A/C. There's a bracket from the A/C compressor that goes down and bolts to the top of the exhaust manifold. The replacement I got had correct casting number, but doesn't have the hole drilled and tapped for the A/C

bracket in the square "boss" on upper side of manifold. Does any one know the correct angle of the exh. manifold mounting surface on the head, in reference to verical? I would need to know this to set up a jig to hold head at proper angle, then drill and tap a hole in the vertical plane. Also, I know I'll probably have difficulty with at least one bolt when removing them for replacing the manifold. Any gotcha's or advise to make

this process as painless as possible? I REALLY don't want ot have to pull head because a bolt wrung off! Thanks, in advance, JR in N.C.

Reply to
JR
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Reply to
Jessie Herrera

On Wed, 23 Feb 2005 02:56:54 -0800, Jessie Herrera rearranged some electrons to form:

Or even better, the Pythagorean Theorum.

Reply to
David M

I have exactly the same set up on my '73 F250 XLT with the 390 engine. However, the bolt hole on my exhaust manifold is virtually perpendicular to the flat surface of the horizontal boss. Do you still have the old manifold? If so that should give you a real good indication of where the hole should go. If not simply bolt the bracket to the back of the A/C compressor and see just where the hole lines up on the exhaust manifold. I'd simply punch a mark, drill down a half inch or so (no more) with a 1/8" to 3/16" bit as a starter hole. Remember, you're drilling cast so it will drill differently than standard mild steel. The drill tip needs to be dressed much flatter than that used for steel. It seems to me that the hole is tapped 1/2-13. This can be a problem if you don't have a "bottoming" tap. I have, over the years, gradually made "bottoming" taps by slowly grinding down a standard tap. If you do this be sure to take your time doing it since you can change the metal characteristics dramatically if you get the tap too hot. Secret: grind a little then cool quickly in oil. Grind some more, etc. Try not to let the metal get hotter than you can stand by holding it about a half inch from the area you are grinding on the tap. If it gets hot, stick it in the oil. Good luck.

Reply to
Ernie Sparks

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