Buick V6 smog equipment????

I recently picked up a parts donor '68 V6 CJ5. The VIN is stamped 'S' for smog, and the V6 looks to have had smog equipment on it at one time (but is now long gone). What were the small (~ 3/8") lines for in the heads just above each exhaust port? My V6 has been running a while with the smog junk removed, and those lines were cut and crimped. I'd be inclined to just properly plug them. Any thoughts? Are the smog heads any different from non-smog in performance?

 

there are several threads regarding how to plug them. I do not remember the size, but I got my plugs at a hardware store. I do remember that they are NOT pipe threads, rather a bolt size. I got some allen head screws that fit in so nicely, it looks like they came from the factory that way. Do not know of any difference in performance in the smog, non smog, but someone else might chime in on that one

cheers

 

1/2 -13 threads.

 

I used allen head set screws If you get the right length they bottom out in the hole and fit about flush to the head. They are coarse thread but don't recall the size 3/8, 7/16, or 1/2. a little antiseize won't hurt either.

 

The allen head plugs sound like the trick, thanks for the input.
What other smog stuff might I encounter? I know it had the fuel return line from the carb back to the tank, and I see a heat spring on rear of the passenger side exhaust manifold.

 

The spring is for a heat riser. When the engine is cold the heat riser has a flapper inside the manifold that forces hot air up to heat the intake faster and to atomize the fuel better. Chances are this no longer works as most I have seen are rusted beyond repair. From what I have read about the return line to the fuel tank it was to prevent vapor lock by keeping cooler fuel running through the system. IMHO I would keep the return line.

 

X 2,
most are probably rusted stuck, but hard to say if its stuck wide open or closed or somewhere in between. I took the flapper apart and removed the cross shaft and brazed up the holes.