I've been looking at new transmissions for my 68 coupe project and I hoping someone can answer some questions for me.

1. They list the transmissions as "pan fill" and "case fill", what is the difference?

2. Are there advantages of one over another?

3. What type was the original transmission?

Thanks for the info.

 

Your original was a STEP-case with a case fill. The truck trannies were a FLAIR-case with a pan fill. Yours came with a 157 tooth flexplate and the Flaircase came with a 164 tooth flexplate. In 67' they changed the 24 spline to a 26 spline which was stronger. Both flair and step can be modified to hold up to lots of torque. It's a lot easier to keep and stay with the STEP case for ease of converter choices. The Flair case and Step case do not interchange on converters and most manufactures make only the step case converters.

 

Mustangs came with a c4, FMX, or C6. All 3 speeds - C4 is most common and preferred of three by most. Lighter & more parts available. Others options are out there if you want to go with overdive - more expensive but good option if you want to go with rear end gearing smaller than 3.5.

Good article on c4s

http://www.mustangmonthly.com/techar...ion/index.html

 

Is there a resale market for original "Fomoco" C4 transmissions? Are they worth more to builders doing an original restore than a more current C4?