Hello,
This my first post, so here goes I have 1950 Ford F1 with a flathead v8, c-4 transmission, 390 holley carb on an offenhauser intake my problem is that the tranny won't shift into high gear, I have 1st, 2nd and reverse. I am not sure what year the tranny is but the modulator has two vacuum ports on one larger than the other and the carb has three ports one behind the choke one in front of the choke and the pvc port, I have hooked these up several different ways and not getting any different results any suggestions would be greatly appreciated and thanks in advance.

 

Welcome to the forum!

I doubt the vacuum modulator is the issue; you would have a greatly delayed 1 - 2 shift and then it would bang into 2nd. HARD. Off hand I would suspect a bad band, servo, or control body. I assume you've checked the fluid level?

 

The fluid is full and also the transmission has been rebuilt,not quite sure if the correct modulator valve was put on and also on what ports should i be running the vacuum lines?(carb and tranny)?