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Best Shift Points?

1K views 2 replies 2 participants last post by  WkStill 
#1 ·
I recently put a 4r70w in my cougar..

Motor: Pretty much stock exept a couple things..
1985 Ford Mustang 5L 4BBL engine:
Rate by ford as
210 HP @ 4400 RPM
270 ft/lb @ 3200 RPM

Now, What has been changed..
Ignition:
MSD 6AL Box, Billet Dist, MSD Wires, Timing Box.. (for minor timing adjustments)
Fuel:
Edelbrock Performer 302 (pretty much the "stock intake")
Holly Avenger 670 Carb
>Front Jets Upsized to 65 from 62
>Rear Jets Upsized to 68 from 65
Exhaust:
Original Mustang Shorty Headers
Custom 2 1/2 Exaust (True Dual) w/X Pipe. No Radical Bends
No Cats, Flowmaster 40 Series Mufflers..
Other:
Electric Fans, No "blade" on the water pump.
200Amp Alternator..

Rear: 8.8 w/3.73 Gears w/Limited Slip.

Where should I set the WOT Shift points too?
Right now 1-2 is at about 5g, 2-3 is at 4.5g, 3-4 is at 4~4.5g
( i stop getting peddle happy at 85mph..)

Math Stuff..
(maybe a little off)
1-2 Shift 5000@38.7MPH (rpm drop too 2700)
2-3 Shift 4500@63.9MPH (rpm drop too 2900)
3-4 Shift 4000@88.0MPH (rpm drop too 2800)

I have not dino'd my car yet.. gonna do soon..

Are these good shift points? or should i tweak them a little? the motor was designed to be in front of a Manual tranny. And it was a dog in front of a C4 w/2.73 gears... But now gets up and goes!..
 
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#2 ·
WkStill said:

I have not dino'd my car yet.. gonna do soon..

Are these good shift points? or should i tweak them a little?


you can tweak then now, but the dyno will tell you EXACTLY the correct shift points.

The PERFECT shift occurs at peak hp, and at the beginning of the next gear, it is at peak torque. You might get lucky, but you'll have choose between:

shifting above peak hp and going to peak torque
shifting at peak hp, and going below peak torque

Since your 5L is fairly stock, I would go with the second option.
 
#3 ·
Thanks Greenbird,

Thats what i thought, I don't like my 1/2 shift anyways (it feels too late!)..

I was planning on getting dino'd today. but had ran into some minor problems putting my 11" rotors on my car. I need to make a note to eric @ coolcats to update his article, in order to do the swap on an 84, you must use the mustang upper strut mounts and struts.. (and make a new hole..).. other wise you have to play will spacers in the struts, and the strut is too long for the 11" spindles.. (its a 1/2 lower..) And since my front of my car sits high? which i have NO clue why. (org v6 car w/c5) i didn't want it to possible sit higher.. (which i doubt would happen anyways)..
 
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