While installing new headers the stub pipe at number 1 cylinder contacted against the push rod tube and it now leaks oil at the cylinder head end.

I have installed push rod tubes on an engine out of the car, but what are the options for fixing a leak in this location in situ?

Big boo boo.

Simple.
Remove valve cover
Remove rocker assembly
Remove push rod in offending one you want to fix.
Take a pair of vice grips and grab the tube, not hard enough to crush it, but hard enough to hold it tight.
There is a lever action you can do on some of the tubes if there is room, otherwise it's a hard yank, and the tube will come free.
Twisting helps also.

Then replace the seal
Put it all back together and set your valve lash again.

You are grabbing the tube from underneath, so your headers may. Ow be in the way....but it can be done....

And on some of them the tube and even the push Rod don't come all the way out...
You don't need to take them out to replace the seals, just need them out far enough to work on them.

Rich said it right

Yup, they can just come halfway out of the head. Leave them hanging from the cylinder head, you can access both ends and replace the seals there. You don't even have to remove the pushrod, just leave it in the tube, but make sure it doesn't fall on the ground.

--DD

While they're apart you should probably reach into the bores where the o-rings seat. You may find some deposits that will lead to another leak if they aren't removed. The o-rings need to move a bit as the engine heats and cools, so that bore has to be smooth.

Thanks guys.
I could only envision it on the bench and doing the job in textbook order.
It makes sense now and should just take an afternoon.
Old dogs need to learn new tricks to keep the brain functioning.

At the risk of sounding redundant, make sure you have the Pushrod Tube Retaining Clips. Mine simply didn't have the clips. I went through several tube seal replacements before I even realized there such a thing.

Hijacking this a little-can it be done on a six? Obviously no push rods to deal with, but it's been a long time since I've been in that area.

I'm thinking that's my problem. If I let the car sit for a couple months without running it, I end up with a big oil pool under the passenger engine side. Thinking I get leak down from the oil tank and it fills the sump.

On a 6, it's an oil return tube, you have to replace with an expandable oil return tube.

http://www.pelicanparts.com/techarticles/9...return_tube.htm

And on that note, MAKE SURE you consult pictures of the spring properly installed. I did pushrod tubes in the car and thought I had it right. Unfortunately one portion of the spring was rubbing on a pushrod tube. Within about 1000 miles I developed a backfire from the #3 cylinder. I ended up pulling the engine only to find out that the groove worn into the pushrod was actually allowing the retainer spring to put just enough pressure on it to keep the valve closed at higher RPMs.