[Archimedes]

I recently put a 750 cfm Holley on my 1967 Ford Mustang 289 with a C4 Transmission. I also put on a hi performance intake as well. ever since, my transmission will not upshift or downshift, and it slips out of any gear a lot. whats wrong here? There is a kickdown on the carb which is not active because on a 1967 the kickdown is connected to the petal linkage. thank you for your help.

 

[SuperDave]

Got your vacuum modulator hooked up? It is the vacuum line from the intake manifold to the tramsmission.

 

[old 67 worker']

not enogh vacuum, w/new mods,? i wouldn't think so ? or just like 'S D" said, "the vacuum is hooked up in the wrong place or not at all ." let me know........what it was.

 

[iniguezs]

I have a holley 4412 and it kind of has been doing the same for me with my C-4. I have a full manifold vacuum on the carb, is this an okay source for the vacuum? What do people think? I do know that when I changed the spark vaccum to the right spot on the carb, the engine and the carb worked better. I took off the vacuum off of the tranny, because I didn't know what it did. I took it out for a spin and couldn't get out of the 1st gear. I havn't put the other tube back, due to not really knowing where it goes. But I did see a drastic difference in changing gears.