I just took my 67 on it's first street legal voyage after it's restoration... working the bugs out. The C4 was rebuilt from it's original 6-cylinder to an upgraded 289. It shifts into forward reverse and neutral great, but when driving won't go out of 1st. I'm going to be off a couple days next week, and am trying to get a list of things to check besides the fluid. How does the kick-down on the edelbrock 600 affect this, and what adjustments do I need to look at? My body shop did the engine tranny install after painting the engine compartment, but it's up to me to get it tuned and running right.  

It sounds like you are relying on your shop to fix your Mustang for you.  That's OK.  However, if your shop overhauled your C4 and it won't shift right, that is their fault and the adjustments should be on their nickel.  The kick down has nothing to do with the C4 being able to shift from first to second to third.  That only comes into play when you stomp it and the carb and tranny race to a new RPM by shifting back to  2nd and the carb is opened to full.  If it is a 4 barrel, the secondaries kick in.  Take your car back to the shop and have them fix their *** up.  

Check your vacuum modulator. If no signal or ,,a leaking modulator is present then the trans thinks it is at wide open throttle and only shifts on the centrifugal governor at the wide open throttle shift points. Make sure you have a vacuum signal and check the modulator with a vacuum pump to see that it holds a vacuum when its pumped up. If not replace it.  

"soaring3" I myself do not have the ability to paint a vehicle with a show finish, so for that reason I sourced the paint job out to a shop. For an extra $250 they pulled my 6 cylinder & trans, stripped & painted my engine compartment, and dropped the 289 and a rebuilt c4 I provided.

I thought when I stated "it's up to me to get it tuned and running" this would be explanation enough to get some information from the site to point me in the right direction.

In the future I would encourage you, before you give your infinate wisdom, to put your thoughts in check and think if I can't answer the question posted... then maybe I shouldn't comment at all. FYI, that same **** shop just GAVE me a 65 fastback rolling chasis for my next project... have you ever had a **** shop do that?

"mechanicalguy48" thanks for the information, I'll look at both the modulator and vacuum hoses. Anything else you can think of would be greatly appreciated!  

I have had problems with C4's also, I guess we all have. They get cranky from time to time. Did you fill the torque convertor before placing it in the trans?  If not, thats a problem.
Try this forum http://www.fordmuscle.com/forums/archive/index.php/f-207.html
They have some good info. You might look at your line pressure also. The forum will tell you more.  

Last night I crawled under is and realized I have no vacuum line at all. I put a line on and ran it to an vacuum on the carb, just to see if it would make a difference, and it did. It now shift close to when it should, but choppy. I plan on putting a vacuum adaptor on the intake this evening to see if I can't get it shifting smoother with a good vacuum. I'll keep you posted.

I'm not sure if the shop out the fluid in the converter, but I'll certainly keep this in the back of my mind if the vacuum doesn't fix everything.  

Well if its shifting then it has fluid in the convertor. You probably hooked the vacuum line up to the carb to start with ,,,that wont do. Be sure you hook the vacuum into the manifold like you said there, it needs a constant signal. Like I said, without a vacuum signal it will only shift on the centrifugal governor which means it will shift at 4000 rpm or whatever its set at for wide open throttle. You can adjust the modulator for shift firmness, but I forget whether its in for firm or out for firm but that forum I gave will have the answer.