351W FMX top speed???

[FMACHI 10]

The Mach I seems to top out at 100MPH. Is this about right for this set up. Not too sure on the diff ratio, but would it make a huge difference.

 

Also I recently had the Motorcraft carbie tuned and dynod for curiosity.

 

Max power was 104kw @ 80mph, and max torque 678 Nm @ 35mph.

 

Don't know what the problem is cams??? But the tourque drops instead of climbs. It drops gradually to 400Nm @ 90mph.

 

Any ideas. I might end up putting another post up regarding this once I bolt up the Holley.

[Spoofty 10]

Torque is made in the lower RPM range and will drop at the higher RPM's. A stock motor would make most torque around 2500-3000 and most power around 4500. Most of the mustangs had a top speed rating around the 100-120 mark. So yours dosn't sound that far off.

More power is easy if you want it. Headers, exuast and intake would wake it up nicely. Cam is a little more involved as you normally need to replace the valve spring and you have to get everything out from in front of the motor like the radiator. Just a little time consuming and you need special tools (valve spring compressor).

[buening 63]

Depends alot on the rear gear ratio. Are you running 4.11 or 2.79 gears? The top speeds between the two are staggering. I've had my fastback with 2.79 gears past 120mph and still had pedal to go. I wouldn't recommend going that fast, because the front end becomes EXTREMELY light and is easy to lose control. This was back in my stupid days when i was 16 :scared:

[Spoofty 10]

Even with high gears it's tough for a stock motor to go much past 120. I've had my speedo on the stops (my stupid days). With 350 gears at 6000 rpm in 4th gear but my motor is also pushing 360 hp.

My front end use to float real bad at high speed. Now with the front spoiler on it's completely stable, no floating at all.

[bnickel 10,004]

i've had mine to about 140mph on the speedo, basically it was down near the middle of the speedo on the 120mph speedo, waaay past the 120 mph mark. also back in my dumber days. basically stock engine except for a 600 holley and 2 1/4" duals with 3.25 gears and stock size tries. i'm sure the speedo was probably not correct though because of the gear change but the front end did get really squirrely. i'm going to guess it was closer to 125-130 than 140. the same engine in my 70 cougar did the same speed according to the speedo and the cougar had a stock 3.00 rear and stock size tires. i do remember the stock replacement cam didn't have the same specs as the stock cam though, slightly more lift all around and slightly more duration on the intake side but less on the exhaust side. so the engine may have been a bit healthier than stock even though it had less compression than a stock 4v motor since it had the dished 2v pistons.

[FMACHI 10]

I'm not sure on the diff ratio, I'll check the build plate. But then again, it may have been changed. I will be changing cams, but only when I'm rebuilding the motor. I'll also be converting to LSD if I have traction problems.

Is Spoofty the only member that's experienced more stability due to the front spoiler. I'm keen to get one, and that's a good reason.

What about rear spoilers, do they also help? I thought both were mainly for a more aggresive stance.

David.

[bnickel 10,004]

the spoiler was made for exactly that purpose, in fact both the front and rear were. they do both help greatly with high speed stability, although a more rigid front spoiler would help even more at higher speeds but most of us will never get our cars going fast enough to really warrant any more of a fromt spoiler than the stock style piece.