See my sig...

 

How do you guys like the 351? And what is with the popularity of the fmx?

 

The 351 is a great engine but I wasn't aware the FMX is a popular transmission. It is what most of our cars came with stock. The FMX was originally used in truck appications I believe, and was put into mustangs because it could handle the extra power and torque of the 351 engines. The C4 couldn't handle it as well, and the C6 was mainly just for big blocks and eats up too much power. The FMX is thought of as a pretty beefy transmission, most of them are 40 years old and still going strong. Mine was rebuilt and it works fine, except it shifts way too fast unless you step on it. I don't know if that is inherent in the design or there's an adjustment that could be better.

The main problem with the FMX is it is really really heavy with its thick steel casing. It also apparently needs a few more special tools that some transmission shops don't have.

 

David, you need to adjust your vacuum modulator. Get under and pull off the vac tube and stick a jewlers screwdriver or a smaller flat tip screw driver in there and adjust it one way or another. I dont remember which way is for a longer shift.. take it for a spin and see how it feels.. Mine did the same thing until I adjusted it. It wouldnt stay in second gear for more than 3 seconds.

 

That's what I heard and tried to do that but I don't think my vacuum module has an adjustment. I read somewhere that only some do? But I'm not certain on that fact. I might have had a screw driver that was just slightly too big, I only tried it for a minute or so. Maybe I'll get under my car this weekend and try it out again...

If not I guess I'm going to need a new vacuum module? I believe it just unscrews and screws back in (plus there's that one pin that falls out... I remember that lol)

The other thing I read before on what people did was take that pin out that's behind the module and they grind like an 1/8th of and inch off and it works