I've been following this post and you guys have come up with some great suggestions, on conversions, lines etc. I'm going to order some parts today, and could use some additional advice.

I obviously have a freon leak, I also have a lot of heat coming into the car from my BB & headers, I will be ordering a new heater/AC controller, all related vaccum lines, and AC lines. My biggest problem is that my heater/AC fan sounds like it's on high, but very little air comes through the vents. I haven't found a source for the AC hose/ducts, and I can't find a AC/heater motor with the fan for a 74. Will a 75-78 unit fit ?

Thanks guys 

According to the information I have, blower motors from '68-'76 w/ac are the same, and '77-'82 are different. That's just the motors.

You may have a bad blower motor resistor...it regulates the hi-low motor speed. First pull the plug and clean its teminals...sometimes that will fix it...it did mine.

Thanks Gunslinger, the blower sounds like it's working fine, but very little air comes out the vents. I will check the terminals, it can't hurt anything.

BTW, if you remove the Poet and Mystic form your discription, and add foul mouth, and disfunctional, you'd be discribing me !  

Your problem sounds more like a diverter problem.  There are several vacuum controlled doors that direct air to different vents within the car.

Either that or the vents are all cracked up or the seals are bad and the air is just blowing out under the dash instead of our through the vents.

I agree

[QUOTE=After Shark]

Your problem sounds more like a diverter problem.  There are several vacuum controlled doors that direct air to different vents within the car.

Either that or the vents are all cracked up or the seals are bad and the air is just blowing out under the dash instead of our through the vents.

[/QUOTE]

I believe you guys are correct with the vent thing. Interestingly, I just read an article on that very same topic. I also ran into to C-3 owners at a cruise night on Saturday, one was a 71, and the other was a 74, both had BB with headers, both had the same problem, and the both of them resolved the problem by fixing the vents. Unfortunately, it looks like more than I can handle,  so I'll have to find a good Corvette shop to do the job.

Thanks guys  

Another common problem on A/C cars with low air flow is when the evaporator collects dust particles due to the condensation build up, and over time plugs the fins and decreases air flow, I have seen cars completely covered in a dust film, with almost no air flow.  The only way to clean them is to remove it and wash it.  The other thing to check when its out, make sure no corrosion has started due the dust film holding in moisture, could become a future leak.

Thanks guys,

I'll be taking apart the whole dash, I've ordered all AC vacume lines, firewall gromet (?) etc. I'll keep you posted.