TeamPontiac79

Hey folks, I believe I have a burnt exhaust valve on the driver's side of my 302. It's a bone stock original with 72k miles. Only thing changed internally was the timing chain. I am on the road far from home, and don't have compression/vacuum gauges available. The problem has been persistent from beforw I left, but getting worse. The ignition components are new or verified (new plugs, wires, cap, rotor, recent points/condensor, original coil). The engine has a pretty regular miss when decelerating, cruising, or accelerating lightly. It seems to go away while I accelerate spiritedly or hammer it, so under a heavy load no vacuum condition is when I don't notice it. It's also less noticeable at idle, but definitely still there. I'm also getting the characteristic popping at the tailpipe, and a piece of paper placed at the pipe shows it is actually a momentary sucking. Car has dual exhaust, and it's only doing it on the left. Is there anything other than a burnt exhaust valve that can create this condition? I'm thinking not, but wanted to toss it around here before putting a major engine service on the to-do list.

The speaker in my dash had been cracked for some year, which really annoyed me. My dash is dark brown and since I live in Denmark, buying and dyeing a new one would cost me a lot.
 
So i made a cheap solution I wanted to share:
 
I cut out all the area of the dash with the small holes for the dash speaker, which was completely cracked.
I then bought some speaker mesh for a 6x9 JVC car speaker. I cut and folded it to fit the hole. I realized that there was about 9mm room from the edge of the dash to the speaker mount underneath, so I folded it twice to make it a usable space.
Then I got some thin speaker fabric to place underneath the mesh, so the speaker underneath isn't visible.
Finally I got some 2mm PVC sheet, that I cut a frame out of, to cover the edges.
And now I have a new place to lay my sunglasses.
A cheap solution that cost me about $25, just wanted to share. ✌ï¸

If you stick with a York compressor, I would use the R12 you still have.  If you want to use R134a, I would consider a different compressor, Sanden maybe.  I've seen kits in the NPD catalog that reuse your original under dash factory A/C components.  But that would be much more expensive than buying a rebuilt York compressor.  Since R134a systems use more efficient condensers and evaporators, if you need any of those components get something compatible with R134a at least for future if you use the R12 at this time.
 
It's been my experience an R12 system converted to R134a while maintaining the R12 condenser and evaporator doesn't work as well.  I have also seen several GM R4 compressors originally for R12 on systems converted to R134a not last very long.  Not because of an oil compatibility issue but I think because R134a operates at higher pressures.
 
Lastly, since the molecules for R134a are much smaller than that of R12, the hose fittings on older R12 systems do not seal as well with R134a.  Sometimes, small leaks at fittings that would drain a system in a year cannot be stopped.  Fittings on R134a systems typically have 3 or 4 o-rings to form a seal as opposed to one o-ring or a flare on an R12 system. 
 
Whatever way you go, remember to flush any old lines and components before assembling, and evacuate the system for about 30 minutes to remove any moisture before charging.
 
For what it's worth, that's my 2 cents.

Check out the NPD car collection in Ocala Florida.

Great idea and a nice looking car. Metuchen , NJ., Myrtle Beach and Daytona come to mind on your way to Key West. (Of course, there's at ton of good stops on the way, not all Mustang related.)

Thanks for the replies folks. I very much agree with the negative sentiment towards the rubber plugs, but I think I'm going to go that route for now since that seems to be the general concensus. I don't want to take a chance pulling the manifold. Just about everything I've touched so far has had some level of failure, and I haven't the time for a can of worms right now. I'm pretty sure I can get the old ones out, and sneak the rubber ones in with just removing the motor mount and lifting the engine with a jack and block of wood as mentioned. I hate using temporary fixes, as they often become more permanent than not. I'm getting closer to having a proper work place though, and a strong desire to refresh the engine. Perhaps next winter it'll get done right!