'77 Vega Emission hose question

[vegiguy]

Did all '77 low altitude Vega's engines have pulse air valves and thermal vacuum switches as shown in the shop manual emission diagram? Mine doesn't and, although a previous owner has monkeyed around with the vacuum lines, it doesn't appear to have any provisions for these devices other than a branch on the crankcase vent tube for the p.air valve hose. I'm restoring this car to original and I'm trying to figure out how to route the vacuum lines without resorting to plugging everything off which doesn't look very original. The car doesn't have A/C; no power brakes or power steering either. The engine appears to have been blue at one time so I'm sure it's a durabuilt.

[kgroombr]

I am pretty sure that all 77s had pulse air. I had a 77 engine where someone screwed plugs in the head where the tubes once went. It was hard to see until gettting really close.

I have heard that because of the pulse air injection on the 77 models, the design of the head was prone to cracking around the ports and water could leak into the engine, so if this happened, it is possible that the head was swapped out.

Ken

[vegiguy]

That may be what happened on this car because I can't see anywhere where the tubes could go, even after I cleaned it up good and removed the carburetor. Were most of the heads replaced with older model heads or did GM have a replacement head available for this purpose without the pulse air?

[kgroombr]

My guess if Chevy replaced the head, they would have replaced it with the correct one with pulse air injection (mainly to meet emission standards). Probably was replaced by another shop or prior owner. If you are looking for an original 77 head, I will keep a look out as I see them every now and then.

Ken

[vegiguy]

I'll probably just plug off the p.air tube and bypass the vacuum switches for now. Finding a GT gauge cluster that doesn't cost an arm and a leg (like the ones on eBay do) is more of a priority for me right now. This got ruined by a previous owner. If you find one of these clusters please let me know.

I owned this car back in the '80's when I was a student, then sold it off later. Of course then it didn't get very good treatment and went downhill. I found it again a few years ago and bought it back for sentimental reasons. I always liked this body style. So now I'm trying to get it back to square one.

Thanks a lot for your input.

Greg

[cos2482]

Greg,

For a little more information about the 77 140 Pulse-Air head, check out this previous topic "Stock Vega Pic. needed":
viewtopic.php?f=16&t=22409