Is it possible to take of the valve spring and change the oil seal on a Ford 302 from 1972 without separating the ingine

 

Yes, but you have to take care not to drop the valve into the cylinder. If that happens, the heads have to come off. There's a couple ways to do this. One is to install a fitting that replaces a spark plug on the cylinder you're working, and apply shop air pressure. This holds the valves up. Another is to stuff rope or clothesline into the cylinder, knotting the end for easy removal. I used that method and it works good. About 18" of 1/2 rubber vacuum line, stuff it in the cylinder at TDC. I like this method, because I can take a break or stop at any time and not worry if the air pressure is going to bleed off overnight or something like that.

With the heads installed, there's only one or two valve compressor tool types that will work. These work "OK" but take your time. Don't get impatient and lose the keepers down inside the engine or watch them fling across the garage. There's 16 of those little guys.

Replace the valve springs with new ones too while you're at it, they get weak after long use. Not expensive. Shim them up for correct "installed height", and engine should run noticeably better.

 

In addition: remove both rocker arms on the cylinder hat you're working on, put some paper towels in the oil return holes (don't forget to remove them), have a small magnet near by.
https://www.summitracing.com/parts/o...hoC98IQAvD_BwE
I've used one like this many times.
The OTC 4573 also shown is another type that works well

 

What about the valve will you do it the same way as described with the vacuum horse or air pressure

 

Yes. The trouble sometimes with using air pressure is that if the piston is not exactly at the top (TDC) when applying air, the engine will turn and the piston goes back down (BDC).
The rope or vacuum hose might work better.

 

Then put in the rope just before the piston is in top and then turn the piston for top after I have put it into the cylinder

 

Do you guys have an picture who show with one of the valve is intake and exhaust

 

I don't have any pics but, usually the exhaust is the one above the exhaust manifold port