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Discussion Starter #1
Hello,

I am going to be building a 351w in the 400-420hp range and am going to have the get a new transmission to handle the power. I figured I should go ahead and convert to manual from my automatic. My question is what transmission would be best for the job and would fit my 69 coupe. I also want the cheapest route if possible. Is getting a used t5 and sending it somewhere to be built stronger a better idea?
 
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Hello,

I am going to be building a 351w in the 400-420hp range and am going to have the get a new transmission to handle the power. I figured I should go ahead and convert to manual from my automatic. My question is what transmission would be best for the job and would fit my 69 coupe. I also want the cheapest route if possible. Is getting a used t5 and sending it somewhere to be built stronger a better idea?
Is it a better idea than what?

If you don't beat it, a T5 is ok providing it is from a V8 car and not a 6 cyl, so check the numbers on it. You can pay for better/stronger gears. You can also get a T6 if you are going to beat it.

Gears

G-Force Transmissions - Free Shipping on All Orders @ JEGS

G-Force Transmissions and Long Shifters


I WOULD ALSO RUN A MCLEOD ORIG 3 FINGER STYLE CLUTCH PLATE. IT WILL COST YOU AROUND $350.00. A diaphragm clutch plate will be a headache.
 

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Discussion Starter #3
Thanks for the response! you seem to always get to my questions so fast! I meant a better idea than buying a completely aftermarket brand new transmission. I really like the G-Force you linked me. Those prices are pretty freaking good! Hopefully all the stuff i have to buy to go from a auto to a manual wont be too much
 
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No prob you're welcome.

My guess is around $800.00 for all the stuff .like linkage, flywheel, clutch pedal throw out bearing, clutch fork, bell housing, shifter etc.. You also need a T5 conversion kit around $250.00, plus the $350.00 clutch.
 

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Discussion Starter #5
yikes! why does his hobby have to be so expensive! It's almost impossible for really young people like me. Thanks for the info man
 

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Because you are not satisfied with having just a stock Mustang. You want 'the upgraded kitchen' just like on HGTV.
 

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Discussion Starter #7
Because you are not satisfied with having just a stock Mustang. You want 'the upgraded kitchen' just like on HGTV.
Hell yeah I want the upgraded kitchen hahaha. I love my car how it is but I'm trying to turn it into my dream car. Which involves having power and having a manual. I'm trying to have this car my whole life. When I'm older I'll most likely going to have another daily driver but I still will have this
 

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T5s don't stand up to high horsepower that well, especially if you tend to reef on them. The case tends to flex, misaligning the gears, causing them to strip. A TKO 500 or a T56 will withstand your power levels.
 

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Discussion Starter #9
T5s don't stand up to high horsepower that well, especially if you tend to reef on them. The case tends to flex, misaligning the gears, causing them to strip. A TKO 500 or a T56 will withstand your power levels.
Oh thanks for the heads up man! That would actually work out better for me because it's cheaper than the GeForce t5. I saw the tko 600 which has a lower first gear ratio. What exactly does a lower first gear do. Also will a tko500 or 600 fit right into my 69 coupe? I appreciate it!
 
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you do NOT want a lower first gear, the first gear is already too low in the t5. if you run 3.73 thru 4.11 gears with a lower first gear than a t5 it will be so low it will be almost useless.
 

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Discussion Starter #11
you do NOT want a lower first gear, the first gear is already too low in the t5. if you run 3.73 thru 4.11 gears with a lower first gear than a t5 it will be so low it will be almost useless.
Thank you, Alright so the tko 500 is the one to go with. But I would also like to know how the first hear relates to the performance. So would a low first gear be sluggish of the line or something?
 
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you will get lots of opinions on this.

the short story is, the lower the gear the faster you have to shift to second. i see no point in having to shift to second at 16 mph with my foot on the floor or at 10 miles an hour when accelerating normally.

there is an optimum gear ratio for each set up and a 351 has a lot more torque than a 289 or 302 and can pull taller gears better.
 

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Discussion Starter #13
you will get lots of opinions on this.

the short story is, the lower the gear the faster you have to shift to second. i see no point in having to shift to second at 16 mph with my foot on the floor or at 10 miles an hour when accelerating normally.

there is an optimum gear ratio for each set up and a 351 has a lot more torque than a 289 or 302 and can pull taller gears better.
Oh okay thanks for making that easy to understand. Yeah it would be annoying to have to switch gears that fast after hitting the gas
 

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Discussion Starter #14
Oh yeah also would I be able to use most of the same parts to convert to a manual with a tko500 as I would use for a t5 conversion? Obviously not the bell housing but what else would have to be different. I'm referring to the t5 conversion kit on cjponyparts
 
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Oh okay thanks for making that easy to understand. Yeah it would be annoying to have to switch gears that fast after hitting the gas
well those aren't exact just an example.


The tko 600 has the best 1 thru 4 ratios imo. 1 is tall and 1 – 2 is a little closer than the others. The 84 t5 ratio is my second choice.

i have driven many 3.35 forst gear trannies with bith 355 and 3.73 and did not like how low it was in 3.73 but did noit liie the other gears either because they were too tall.

TKO-600
2.87 1.89 1.28 1.00 0.64

TKO-500
3.27 1.98 1.34 1.00 0.68

T5 ratios.
84 …..1st 2.95 2nd 1.94 3rd 1.34 4th 1.00 5th .62
85-89 1st 3.35 2nd 1.93 3rd 1.29 4th 1.00 5th .67
90-95 1st 3.35 2nd 1.99 3rd 1.33 4th 1.00 5th .67


Tko 600 in 1st gear, 3.73 gear, 26” tall tire.

Engine Speed (RPM) MPH 3.73 Gear MPH Gear MPH Gear
6500 RPM 46.97 MPH MPH MPH
6000 RPM 43.35 MPH MPH MPH
5500 RPM 39.74 MPH MPH MPH
5000 RPM 36.13 MPH MPH MPH
4500 RPM 32.51 MPH MPH MPH
4000 RPM 28.90 MPH MPH MPH
3500 RPM 25.29 MPH MPH MPH
3000 RPM 21.68 MPH MPH MPH
2500 RPM 18.06 MPH MPH MPH
2000 RPM 14.45 MPH MPH MPH
1500 RPM 10.84 MPH MPH MPH



t5 with 3.35 1st.


Engine Speed (RPM) MPH 3.73 Gear MPH Gear MPH Gear
6500 RPM 40.24 MPH MPH MPH
6000 RPM 37.14 MPH MPH MPH
5500 RPM 34.05 MPH MPH MPH
5000 RPM 30.95 MPH MPH MPH
4500 RPM 27.86 MPH MPH MPH
4000 RPM 24.76 MPH MPH MPH
3500 RPM 21.67 MPH MPH MPH
3000 RPM 18.57 MPH MPH MPH
2500 RPM 15.48 MPH MPH MPH
2000 RPM 12.38 MPH MPH MPH
1500 RPM 9.29 MPH MPH MPH
 

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Also, if a first gear is too low, it will actually accelerate slower than a higher gear. In essence, you'd be using up more of your power to spin up the drivetrain rather than pushing the car. When I had my '94 Mustang, the acceleration difference between 2nd and 3rd was almost negligible because of that. 3rd felt like it had better acceleration even than 1st. Many drag racers start from 2nd because the T5's first is too low. IMO, a 1st gear ratio around 2:1 is about ideal.
 

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LOL, I've been modifying and racing fox mustangs with t5's for nearly two decades...Starting off in second gear on a t5 is a great way to get a horrible time slip.

Really it's what you're used to...the fox guys all run the t5 with the 3.35 first gear ratio, and don't hesitate to run 4.11's on the street all day long...I've never heard a complaint from a fox mustang group about first being too short...you'll get used to it.

As well, the v6 mustang t5's and the v8 t5's have the same power rating..it's the fox 4 cyl t5's you have to watch out for...those suckers are weaker and have a 3.95 first gear!

I've built several t5z trannies for people running 450 hp, and they've never had a problem with them...these were however primarily street driven cars for older guys that didn't beat on them too hard.

The t5z has a nice 2.95 first gear ratio, just like the earlier NWC t5 from 83/84, yet will handle 400-450 hp as long as you're not on slicks every weekend.

As far as gforce goes, consider the Astro A5 t5. Astroperformance.com - Your Manual Drivetrain Specialist

the astro gears are CONSIDERABLY beefier than the gforce gears. Only drawback is that Astro doesn't offer a stronger t5 case...I'd suggest buying the gforce improved t5 case, and stuffing it with astro gears.
 

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Oh geez, I screwed up there. I didn't mean 2:1. I was thinking about that 2.95:1 first gear ratio, then, yeah. I will admit, I don't have much experience with drag racing either, and most of my expertise lies in suspensions.
 

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Discussion Starter #19
LOL, I've been modifying and racing fox mustangs with t5's for nearly two decades...Starting off in second gear on a t5 is a great way to get a horrible time slip.

Really it's what you're used to...the fox guys all run the t5 with the 3.35 first gear ratio, and don't hesitate to run 4.11's on the street all day long...I've never heard a complaint from a fox mustang group about first being too short...you'll get used to it.

As well, the v6 mustang t5's and the v8 t5's have the same power rating..it's the fox 4 cyl t5's you have to watch out for...those suckers are weaker and have a 3.95 first gear!

I've built several t5z trannies for people running 450 hp, and they've never had a problem with them...these were however primarily street driven cars for older guys that didn't beat on them too hard.

The t5z has a nice 2.95 first gear ratio, just like the earlier NWC t5 from 83/84, yet will handle 400-450 hp as long as you're not on slicks every weekend.

As far as gforce goes, consider the Astro A5 t5. Astroperformance.com - Your Manual Drivetrain Specialist

the astro gears are CONSIDERABLY beefier than the gforce gears. Only drawback is that Astro doesn't offer a stronger t5 case...I'd suggest buying the gforce improved t5 case, and stuffing it with astro gears.
so a numerically higher first gear pulls harder, but is shorter? Now I'm in the position of not knowing whether to go with a beefed up t5 or a tko 500. Say I get 3.55 in the rear, 400-430hp engine, that I will drive on the street and will probably beat up from flooring it a lot, what would be the better choice and what first gear would I want? numerically higher or lower? Thanks man!
 
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lol, it gets confusing.

we can all bury you in numbers.

imo its easy to over think things. i suggest you read my previous post again.

if you have a 200 ci 10,000 rpm engine, you want low first gear or it will fall on its face until it gets up in the rpm range.

if you have a 600 ci engine that revs to 5500 rpm, you want taller first gears, otherwise your limited rpms will cause you to shift at very low speeds as i previously mentioned.

i have driven tons of different combos and actually did gear ratio testing for a major vehicle mfg. all my customers liked their set ups and very few liked first gear with in a t5 with 3.73 and none liked it with 3.91. obviously some others like it with even 4.11's though however these mainly people with 302 engines, not 351 or larger.

the first two below are a std top loader from the 60's and 70's fords. the wide ratio had an ideal first gear for street use with all rear end gears imo. the wide ratio was definitely too tall for quick accel off the line with anything other than 3.91 and numerically higher gears. look at the huge difference in ratios from the wide ratio top loader and the t5 with 3.35. it is .57. this is almost the same distance as 4th to 5th in the 5 speeds below. this is a big jump.

if you have a 400 plus hp stroker engine with a 3.35 first gear, a 3.73 or numerically higher rear gear and a typical 26" tall 8" wide tire and traction bars and a posi and you rev it up and dump the clutch, you will roast the bejesus out of the tires and have to shift into second at around 7 mph. i know, i have done this. its kinda stupid imo, but it certainly looked impressive, lol.

both tko's have a closer 1 to 2 than the t5's which helps maintain speed. the tko 600 has a closer 3 to 4 which also does the same thing and many people that are having fun from a stop lite shut it down before they hit 4th anyway because they are going pretty fast at that point. so the close 2 to 3 is good for that also.


Close 1st 2nd 3rd 4th
Ratio 2.32 1.69 1.29 1.0

Wide 1st 2nd 3rd 4th
Ratio 2.78 1.93 1.36 1.0


TKO-600
2.87 1.89 1.28 1.00 0.64

TKO-500
3.27 1.98 1.34 1.00 0.68

T5 ratios.
84 …..1st 2.95 2nd 1.94 3rd 1.34 4th 1.00 5th .62
85-89 1st 3.35 2nd 1.93 3rd 1.29 4th 1.00 5th .67
90-95 1st 3.35 2nd 1.99 3rd 1.33 4th 1.00 5th .67
 
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