Hi All,
Just got a 75 L48 auto a/c coupe from my brother. It has been sitting not running under a car port since around 1992. Had it towed to my garage and now the fun begins. I started ordering a few parts from ebay and some of the popular vendors. My plan is to restore the car back to factory stock over time (with maybe a few internal engine mods). I want to get it running and driving and then replace/repair things as time and $$ allows. I poured some oil in the cylinders and after a few days was able to rotate the engine over by hand by pulling on the belts. I'll have lots of questions to follow and this looks like a great site to get all kinds of help. So my first question would be about the A.I.R. system. I am trying to figure out if my car came with it originally. I read in the c3 restoration guide that some but not all 73-77's had the air pump. I was reading online that some of the engine suffix numbers indicate which ones had the pump. I found the engine numbers on the front plate over the water pump and it matches the sequential numbers from my vin. The suffix from my car is CHB which I believe is an L48 federal emissions? According to a few internet searches all of the CHB engine suffix codes came with the air system. Does anyone know what the correct answer is on this information?

 

Welcome

I don't know those codes, but certainly wanted to say hello!

Some (most) of the guys on this site are amazing. I'm sure you'll get your answer soon!

 

Welcome to the Forum.....Congrats on the '75!

Wait for the experts to reply (I'm new here too)

 

Welcome....... Don't be afraid to ask questions. We all are here to help each other. I have asked and received a lot of great information. Also try and help when I can. Try and find some local to you c-3 owners or go to a local meet up, or make freinds with a forum member close to you. I have met 3 forum members and have a few more that I will meet in the spring.

Congrats on the new ride, have fun.

 

Welcome. Congrats on the new ride. Let the fun begin. Can't say for sure about all 75 vettes but mine did come with the air pump.

 

I did find some local vette clubs online last night. One of them meets in late spring and it is a local cruise night/meet that is open for all to come and browse so I will definitely go to the first meeting in late April. I have to learn to post pictures so I can update my posts when I make progress or need help with something. Too cold up here in MA to do much right now. Waiting for the temps to moderate a little so I can go to town on the brake and fuel system.
Thanks for your encouragement
Jim

 

Hi Jim,
welcome to the fun!! This is one of the best sites to ask for help or answer any questions you have on your new ride. I too am new at this and also have a 75 stingray. My L48 has all of the A.I.R. equipment removed along with the cat exhaust system when I purchased it last Sept. Has dual exhaust like the 74 vette and plan on leaving it that way. My feeling from the research I have done the 75 was the first year vettes came with a catalytic converter system. Any way my car is also stuck here waiting for this winter to end in Mass. have it on jack stands replacing all of the rubber, bushings, shocks, brakes to get her ready for spring.

 

For 1975, CHB simply means 350/165 HP L48 mated to an automatic. I pulled the information from the Corvette restoration guide. By the way, I'm in the process of rebuilding a '75 that was almost ready for scrap. "Small Garage Restoration" in this forum. There are a number of full restoration threads. I'm not shooting for a full stock restoration though.

Welcome and good luck. You'll find a lot of very good support from the great people on this forum.

 

Check the emission label and you should find its GM# 360420 with code AS. This will indicate your A.I.R. configuration. Engine code CHB is called out for an L48 M40 with federal emissions. It was configured with A.I.R. pump GM# 7801149. Also look at your exhaust manifolds and you may find plugs where the tubes where connected.

 

Welcome aboard. Lots of good guys here who are more than willing to help. Hang on to what's left of your wallet and have fun.

 

Welcome to the forum and while ebay can be great, when you can, please try to support the vendors who support this site. We are fortunate to have quite a few supporting vendors on here who help with tech and information and they help keep the site going. I have bought from pretty much all of the supporting vendors here at times, but predominately do business with one of them. There are a lot of knowledgeable people here some know all the hard and correct Corvette facts, others know engines, transmissions, etc, everyone seems to bring something to the table, most importantly and most prevalent is the willingness to help each other out with info etc.

Cant wait to see pics of your car!

 

Another C3 owner... COOL! You'll get lots of help from these guys. If your car already has the A.I.R. then it came with the car. Nobody in his right mind would put one of those things on a Vette if it wasn't original equipment in the first place. For others (such as myself) we find ways to get right of the darn things.

 

Still waiting for the good weather but at least I have been able to do some more research. I have some pictures of the distributor and wiring that is somewhat of a mystery. Perhaps someone could help in this area. Is this an original distributor as seen in the pictures? The coil says Delco Remy which is correct but the wires are spliced together. There is a red wire that is spliced onto the yellow wire going to the terminal on the right I think it is marked BAT. The TACH terminal is spliced onto a wire that is black and goes through the firewall. Would the black wire to the tach normally do this? Seems to me that it should be included in the engine wiring harness.

 

Continuing on with my wiring mess. The front harness is all spliced together with butt connectors. Should there be a plug that connects the front harness to the engine wiring? There are also several wires that are not connected to anything. It might be hard to see them in the picture so I may have to go and re-shoot those pics. The first 2 are in the forward harness picture, the next 2 are near the heater/ac box on the firewall. The ones near the fire wall are black and tan with 2 female spade type connectors. The black wire goes into a three way splice which doesn't look like it was done at the factory. There is also a picture of the under hood courtesy light without any wires attached. Does these wires connect to the forward harness? The other picture shows a tan wire going to the ac compressor ground but is spliced to a green wire? lastly there are no wires connected to the security system key switch. The 2 wires in the picture near the brake booster look like they have brass terminals on them and are possibly from the key switch.

 

Since you have several wiring problems........Click on the link below....

he offers detailed wiring diagrams free if you send him a Personal Message stating the year of your car along with your e-mail address:


http://forums.corvetteforum.com/c1-a...iring+diagrams

 

I have seen lots of information on the seat belt interlock and not sure which pertains to mine. The body build tag says that the body was built Feb 03 of 75. I have read that they stopped the interlock installations on Feb 24th of 75 although I am not sure if that is correct. From this picture of where the under hood relay is supposed to be mounted above the heater box it sure looks like something was once installed there. What do you think? From all of this wiring mess it looks like I am going to have to replace most of it in the future.

 

Thanks I sent off that message.
Jim

 

I was trying to get the third picture in your post to appear here but "reply" isn't picking it up.

'75's had HEI ignitions which have the coil under the cap shown in the third picture. If you have an external coil somebody added it which isn't surprising with all the wiring that has been done to your car.

Can you post a pic of the distrib with the rotor removed and your coil so we can see what you might have.

 

I will get those pictures tomorrow and post them. Also I took a picture of the capacitor that is mounted on top of the intake manifold right near the distributor. The wire that was on it fell off when I touched it and it had a small plug on it but I can't see where it would plug into. It was not hooked up to anything when I got the car.

 

That's a filter for the electronic tach. It connects to the "tach" terminal on the distributor and the wire to the tach in the instrument panel plugs into it. That is assuming that the original coil in the distributor cap is being used.