Changed gears poor track results

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Adger Smith
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Re: Changed gears poor track results

Post by Adger Smith »

I have never had a 406 on our dyno make power above 6500 with the heads and combination you have.
MHO is you have over geared the RPM power potential of the engine.
You have also lost flash and recovery stall at the shift with the extra gear ratio.
Any time you put more gear in a converter acts like it is tighter on flash and shift recovery.
You must have originally had a good converter/ gear combination for the RPM/ Power range of your 406.
That is barring the rearend break up didn't harm the converter and trans. Could have rolled the sprag in the converter.
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1980RS
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Re: Changed gears poor track results

Post by 1980RS »

Adger Smith wrote: Sun Sep 12, 2021 12:40 am I have never had a 406 on our dyno make power above 6500 with the heads and combination you have.
MHO is you have over geared the RPM power potential of the engine.
You have also lost flash and recovery stall at the shift with the extra gear ratio.
Any time you put more gear in a converter acts like it is tighter on flash and shift recovery.
You must have originally had a good converter/ gear combination for the RPM/ Power range of your 406.
That is barring the rearend break up didn't harm the converter and trans. Could have rolled the sprag in the converter.
You sir are probably right on that, I am thinking of going to a 3.91 gear in a 9" ford rear end. The rear end break was at less then 10mph on the return road and I think it was already loose from the prior race. Will be ordering that also for next year.
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Re: Changed gears poor track results

Post by levisnteeshirt »

1980RS wrote: Fri Sep 03, 2021 12:44 am I had to change out my 4.10's as I broke some parts with the car last outing. Now most of this year and years past with the 8" TCI converter the car hit the stripe at like 61-6200 so I thought the 4.88's would be like 6800, nope the car now goes through at 7400 all else the same, but I changed exhaust form the rear axle system to my Walker Bullets which I have always used like forever. I was mighty surprised by this result. I lost MPH as a result of this even spinning the engine a lot tighter. I did have some problems earlier in the day but it turned out to be a bad set of spark plugs brand new same as the old ones. Put them back in and the 406 would spin to the moon. Is the stator going bad in the converter?
One change at a time pleaseee ,, Im guessing you have a turbo trans since it has mufflers ,, once ya go to a 8 in converter things change. Usually. The converter works harder with a numerically lower gear ratio and now you have a better converter to boot. And throw in a 406 that's another ace in your hand to not need as much gear. What does it weigh ?

Turbo 2.48 1st gear and a 4.10 gear equals a glide 1.82 1st gear with a 5.60 gear.

Had a friend with a back half vega , 331ci , probably 450 hp tops ,, 2600 lbs , 31" tall tire ,, Glide ,, when he bought an 8 in converter it had a 513 gear ,, he went 488 it picked up , he went to 410s is was about the same , Tci 8in 5500 stall ,, Not what I expected at all , with a 331 engine ,, wouldn't have believed it if i didn't watch what gears he was putting in it
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