I know someone on here has done a swap from 3 spd to a newer 5/6 speed trans. I have a 68’ with a 3spd and I’m looking to improve upon that. Top loader 4spd around me are getting really expensive. Looking at a newer 5spd and what I will need to do. Dont want to cut car up to achieve this either.
I highly recommend the folks at Modern Driveline. I’d give them a call and they can walk you through all the options. There are many things to consider from how much HP/TQ you’re running to tire size and gearing.
A brand new top loader from David Kee is a very reasonable option for your situation. I would use the wide ratio for anything you plan to drive on the street. You will need the longer 4 speed speedometer cable and this transmission. No other changes required.
Your looking for T5 swap. However there are pros and cons to the swap as you might expect.
Check out modern driveline to get an idea on what all you would need, they can sell you a direct bolt in package that includes everything you would need including a new transmission. Just be prepared its going to bring a 3k price tag in parts alone, but its all new quality parts and the transmission is a good 1900 of that price. Of course you can source things you need on your own as well as a used transmission but I found even a solid used T5 is getting harder to come by now days
Basically you will need the transmission, bellhousing or adaptor plate to use your toploader housing, T5 shifter, clutch, Crossmember, speedo cable or adaptor to convert to electric, Ive seen the Z-bar reused but its advisable to convert to cable or hydraulic setup, slip yoke and driveshaft modification
keep in mind the T5 while great for stock to mild 302s they are not really happy behind something with more power. The rule of them for longevity is about 350hp or so. For a toploader they seem to hold up to much more abuse then a T5 will.
I agree with the toploaders being pricey but you never know what you will find. I had all but decided to do the T5 swap when I got to that point in my project but always kept looking for a toploader just in case. Ended up scoring a deal on one locally that made it a no brainer. As you know its a direct bolt in swap for your 3spd and IMO greatly improves the driveabilty over a 3spd so I felt it was worth the effort to do now even if later I decide I still want OD. I can eventually upgrade to a T5 later if I desired or maybe a t56. Always a the gear vendor option for the toploader too.
Royce does make a good point about entertaining a brand new one as well. Especially for what some people try to offload used toploaders for
I did a t-5Z swap in to my 70 XR-7. The link below is the story. Your project will be a little easier, being your already a manual transmission Cougar.
by DieselD »Basically you will need the transmission, bellhousing or adaptor plate to use your toploader housing, T5 shifter, clutch, Crossmember, > speedo cable or adaptor to convert to electric, > Ive seen the Z-bar reused but its advisable to convert to cable or hydraulic setup, slip yoke and driveshaft modification
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If you buy a New T-5Z from Modern Driveline or Summit Racing your old cable will work fine. Or if looking to get a used one just make sure it is from an earlier Mustang or Ford passenger car. T-5s were put in to Camaros and other brand cars. WHile they can be made to work, you have to modify them, save your self the heat burn. I had to replace my old speedometer cable as the machining tolerances were off ether on the T-5 or my old cable and it would not go in to the transmission. But I used a new reproduction one that was a factory type replacement. Funny how a few thousands can be such a head ache.
You may also want to get a different set of gears in the rear. Mine had a set of 3.0 from the factory. Overdrive was nearly useless under 70/75MPH due to too low of engine RPM. But 1st through 4th was OK. Much more fun now with a set of 3.5 gears.
Good luck with this project and I think you will love it.
Go to mustangsteve.com
He has the best cable clutch setup out there. Also, a rebutil t-5 can be found for under a $1000 with updated parts. Trans crossmember about $75 or less. Bellhousing about $100 used, engine plate, flywheel, use a king cobra clutch setup complete with TO bearing, your c-4 trans yoke will work if you cut it…I think it’s 1 inch or so. Fairly simple easy to do. Should be able to do for under $2000.
I’m slowly crawling through a TKO 600 swap which is replacing the 3 speed in my car. Converting to hydraulic clutch and just installed the master cylinder tonight. I started down the path using the 164 tooth flywheel and stock cast iron bell housing but changed to the 157 tooth flywheel, smaller clutch and AL Fox body bellhousing. My Powermaster starter required a new nose plate and I went with an aluminum Ram flywheel and clutch system as my stock flywheel was pretty chewed up. Tomorrow I hope to have the clutch installed then the bellhousing so I can get the trans in on Monday. I’m using a California Pony cars crossmember. I bought the trans from D&D Performance I pin the Detroit area. I was able to find a buyer for me 3 speed but kept the shift knob for giggles.
Oh and I swapped my rear end for a newly rebuilt 9” with 31 spline axles and 3.70:1 gear and Auburn diff. Should be much better out of the hole and reduce freeway RPM.
From the sounds of it, price of a top loader maybe worth it. I really want to swap to a 5/6 speed but the car is a driver and I have other things I’m wanting to spend more time on then all the mods just for the tranny
My 3 cents worth from having built run raced almost all the possible combo’s
3 speed …suprisingly …its unthinkable to keep this in the car …? A full synch toploader 3 speed is almost a manual shifted C-4 bullet proof will speed shift with no issue 1:1 top gear. Have put many many miles on the 390 3 speed in a 68 6.5 litre XR-7 abusing the crap out of it in my youth
Never ever had a problem. Was advised to run hurst comp plus shifter from a 4 speed and it was bulletproof
4 speed tooloader …I only appreciated the 4 speed after putting a few TKO 600 swaps in fir myself and others. I owned 3 cars wuth them installed two others only 1 of these would shift above 5500 RPM OD is deep and sweet …not being able to speed shift above 5K bad nit beung able to shift at all above 5500 …just terrible…oh and diwnshifting also sucks
T-5 …ah…they are really pretty good until you break it…which you will
Ideal combo IMHO Toploader 4 speed …good clutch setup, 2:73 posi 9 in rear great on the highway …great around town …buy the bullitt soundtrack CD and have fun
I like the sounds of that! I’m in the process of shelving engine upgrade parts. Have a lead on a 4 spd and 9” rear. For fun I took the car to local drag strip in its current 289/3spd. Ran 16.2 @84mph. If I could get the car off the line I bet it would run low 15’s. I’d like a daily driver, blast to drive, fun with the kids and be in the 12’s
Count me as another happy Modern Driveline customer. Badcatt and DieselD are spot on. I also have a 70 Standard (351C) that was originally equipped with a 3-speed toploader. I had the MDL guys spec out all the conversion parts for my T5z swap. Major improvement in drivability - especially the overdrive for highway cruises. Highly recommend looking at your diff gearing, as well. I upgraded my 2.75 to 3.50 posi, and now it screams like a scalded cat.
LOL. Unless you have a pretty big budget, this seems like a tall order.
Not really. I just sold such a car, the 2012 V6 Mustang. And we have a lot more room to grow cubes in our Cougars.
Oh sure, he could buy a Tesla too.
You’re an old hand at wrenchin’ & racin’: ballpark this guy’s budget to take a stock '68/3 speed to a 12.7 quarter mile, while retaining perfect road manners, ability to withstand daily driver traffic, provide full comfort and safety for 4 passengers, etc.