Hitting the strip with a pushbutton 727

[Bill Crowell]

Dumb question about what the big boys do at the strip. Don't laugh. Be a good person and take pity instead.

Backstory: '62 Valiant with a pretty hot 408 stabbed into it. The cam has about 246 degrees of duration at .050 and it's got cast iron, open-chamber "J" heads that have been ported about as much as possible. I built the engine back when higher-octane gas was available at the pump, so we didn't have to worry about quench. (Or maybe it was because we didn't understand quench.) Now I have to run it on a mix of 91 octane pump gas and VP Racing 110 octane, but that's not the problem.

This engine really comes on strong only around 3,000 or 3,500 RPM, so I want to keep the RPMs high.

I believe I have my Bouchillon Performance 3350 kickdown assembly working correctly, and I am happy with it. But when I adjust the kickdown cable so the 727 shifts automatically at a nice, high RPM, the car does go quite well but the cable is so tight that it's pretty hard to press the gas pedal. So, first of all, does that seem normal, or am I doing something wrong?

And when I go to the strip, should I adjust the kickdown cable so it is more loose, will automatically shift at a lower RPM, it will be easier to push the go pedal, and just shift it myself with the pushbuttons instead?

 

[Demonracer]

Shift it manually, it's been down for years that way.

 

[Bill Crowell]

Shift it manually, it's been down for years that way.

Thanks!

 

[pishta]

you want the car to shift at a high RPM automatically, why don't you alter the governor weights in the tailshaft? The kickdown only goes so far and then it stops, ie if your fighting the stop on the kickdown with your gas pedal, maybe a spring on it to give your pedal more travel while maintaining your full kickdown activation.

 

[Bill Crowell]

Roger, roger, Pish! I'll check into changing the governor weights. Thanks a lot.

 

[Darter6]

A&A transmissions has a listing for many different rpm shift governor weights that they stock.

 

[Jadaharabi]

Talk to John Cope of CRT(Cope Racing Transmissions). He's a super guy and can help you.

 

[CudaFactHackJob]

It seems wierd that the kickdown return spring would offer much resistance to the gas pedal. It sounds like it's adjusted too tightly; and it's bending internal parts to allow the carb to open completely.

 

[RustyRatRod]

What I would do if you really want to race it is go to a manual valve body. That's what all the "big guys" did back in the day when names like Dick Landy used pushbutton shifted transmissions. Also remember too, if you still have an automatic valve body and shift it manually, that does work, but the throttle pressure will still be lower than it should be when the shift is made. Just food for thought.

 

[Bill Crowell]

Thanks a lot for the edumacation and the tips, guys. They were extremely helpful, and I really appreciate it. I've got this thread printed out for permanent reference!