A518 conversion on a pushbutton 727

64Imperial

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Hey everyone I've been reading alot of threads that talk about converting their transmissions to 518. Has anyone ever done it on a 1964 Imperial?

Also what kits are out there so I can still use my push buttons? Some of the threads are too old and the links go nowhere!

Thank you in advance!
 
I suspect you might have more issues with the 518 clearing the existing trans hump than getting it to accept the pushbutton cable mechanism? Reason I say that is that I read, a while back, that some modification/enlargement to the trans hump on B-bodies were needed. Might be similar on the '64s?

What rear axle ratio in the '64? Multiply it by .7 (as a general rule) to get the resulting "in OD" effective axle ratio. Might need a rear axle ratio change to a deeper ratio so the OD can be used at normal highway speeds, FWIW.

CBODY67
 
I would normally suggest going to a gear vendors overdrive unit that was attached to a 727 transmission. This avoids the problem of the 518 locking convertor going south at some future date and trashing the transmission. However your '64 still has a rear pump and gear vendors does not make a unit that will work for this application. Imperial services used to make a conversion kit to adapt the later 727/518 transmission to operate with push buttons, but they are now defunct. The 518 transmission has a small block bolt pattern and that means that you will need an adapter kit to fit it to your 413. It would be my best professional opinion that you should keep what you have and avoid trying to cobble something together. If your Imperial has a center console, you might be able to adapt a floor shift to work with the later transmission, but that means that functional push buttons are history.

Dave
 
A518 is a small block only transmission. I don't understand what having the adapter between the front of the transmission and the back of the block does to the flexplate. Does it need to be replaced with something else? Does it pull the torque converter forward so you don't have full engagement at the transmission input shaft and pump?
 
A518 is a small block only transmission. I don't understand what having the adapter between the front of the transmission and the back of the block does to the flexplate. Does it need to be replaced with something else? Does it pull the torque converter forward so you don't have full engagement at the transmission input shaft and pump?
The adapter uses a spacer between the back of the crank and the flex plate so the proper distance is kept.

Dave
 
I suspect you might have more issues with the 518 clearing the existing trans hump than getting it to accept the pushbutton cable mechanism? Reason I say that is that I read, a while back, that some modification/enlargement to the trans hump on B-bodies were needed. Might be similar on the '64s?

What rear axle ratio in the '64? Multiply it by .7 (as a general rule) to get the resulting "in OD" effective axle ratio. Might need a rear axle ratio change to a deeper ratio so the OD can be used at normal highway speeds, FWIW.

CBODY67
My axle ratio is 2.93 and that might be a clearance issue I'd have to measure!
 
I would normally suggest going to a gear vendors overdrive unit that was attached to a 727 transmission. This avoids the problem of the 518 locking convertor going south at some future date and trashing the transmission. However your '64 still has a rear pump and gear vendors does not make a unit that will work for this application. Imperial services used to make a conversion kit to adapt the later 727/518 transmission to operate with push buttons, but they are now defunct. The 518 transmission has a small block bolt pattern and that means that you will need an adapter kit to fit it to your 413. It would be my best professional opinion that you should keep what you have and avoid trying to cobble something together. If your Imperial has a center console, you might be able to adapt a floor shift to work with the later transmission, but that means that functional push buttons are history.

Dave
You can kinda see the rabbit hole I've gone down just trying to work out an idea to see if it's possible! 64 is such an odd year... last year for tapered axles (what fun they are lol) last year for push buttons (love them but it makes a modern alternative hard to configure lol)
 
My axle ratio is 2.93 and that might be a clearance issue I'd have to measure!
2.93 with tall tires (9.15x15) is more like a 2.76 with H78-14 tires, basically. Either way, NOT friendly with an OD trans, unless you're running about 100mph. At that speed, aero load is a lot, which means lower intake manifold vacuum at low engine rpms, which leads to doggy throttle response and such. AND . . . not fuel efficient as the carb is in the power mixture! Not fun! The engine is much happier where it now is.

Just some observations,
CBODY67
 
I have done the 518 behind a 440 in a 63 Sport fury and I have the 47RE behind the V10 in my 70 Fury.

Check out my build thread just search v10 Fury and you will find it.

It can be done in a C body with minimal "adjustments" to the tunnel, cross member, and some trimming on the trans but you will have to know how to cut and weld. Having done the B and the C I think it was much easier in the C. The B you have to cut out part of the cross member. On the C you just need to modify your cross member or I think your Imp has a full frame so it may be easier to make a new cross member. You will need a ball peen hammer to make some dimples on the tunnel but it will not be noticeable inside the car.

To mount the big block to the 518 you will need an adapter or an Ultra Bell bell housing. I went the Ultra Bell in my 63 because it doubles as a scatter shield for racing and I didn't want the adapter because it moves the trans back into the firewall or you need to move your engine forward a bit. The only downfall is you have to cut the stock bell housing off the 518 and bolt the Ultra Bell on at the pump housing. Don't worry it isn't that bad and it is strong as the ultra bell was designed for drag racing. Link to the bell housing J.W. Performance Transmissions 92457 J.W. Performance Ultra-Bell Bellhousings | Summit Racing

I worked on trying to make a mechanism to use my push buttons in the 63 and I got it to work with the stock shift cable for 1st to R but I couldn't get the park cable figured out. In the end I gave up and put in a floor shifter and used 2 toggle switches for OD and Lockup. That project was 20 years ago but I can give you the basics of my modifications and maybe you could figure it out.

On the 63 I was running 4:11 gears and could cruise down the highway at 3000 rpm running about 70 with the OD and lockup on.
 
2.93 with tall tires (9.15x15) is more like a 2.76 with H78-14 tires, basically. Either way, NOT friendly with an OD trans, unless you're running about 100mph. At that speed, aero load is a lot, which means lower intake manifold vacuum at low engine rpms, which leads to doggy throttle response and such. AND . . . not fuel efficient as the carb is in the power mixture! Not fun! The engine is much happier where it now is.

Just some observations,
CBODY67
You are correct if you have a 2.76 gear but the entire point of doing the swap is to run a 3:23 to 4:11 gear and still be able to road trip.

If you are not going to change your gear then I agree there is no point in doing the OD swap.
 
This avoids the problem of the 518 locking convertor going south at some future date and trashing the transmission.

Dave
You can get built lock up converters or you can even order a non lock up for the 518 if you are worried about it. I feel if you are going to utilize the 518 for all it is worth go with the lock up converter it drops the RPM another 200 RPM
 
I definitely would upgrade the gears if I went with the 518, I couldn't imagine the the weak response you would get if you left it alone lol

Mainly I was looking for a little better fuel economy on trips and in town, also the lower rpm would not wear the engine as much. To be honest this may be something I just do in the future.
 
I definitely would upgrade the gears if I went with the 518, I couldn't imagine the the weak response you would get if you left it alone lol

Mainly I was looking for a little better fuel economy on trips and in town, also the lower rpm would not wear the engine as much. To be honest this may be something I just do in the future.
It would feel the same from 1st to 3rd but with the OD and LU on it would try to cruise down the hwy at 1200 RPM and that would not be good.

I can tell you my 63 with the 440 and a 4:11 gear was sooooooooo fun to drive and I could still drive it on road trips.

Think of it like this with your 2.91 gear you are cruising 70 MPH at around 2500 to 2600 RPM and it probably isn't that good from a start. Switch to the 518 with a 3.73 gear and you can cruise 70 at around 2400 RPM and have a car that will be great from a start. It will also help you meet the goals you stated.
 
It would feel the same from 1st to 3rd but with the OD and LU on it would try to cruise down the hwy at 1200 RPM and that would not be good.

I can tell you my 63 with the 440 and a 4:11 gear was sooooooooo fun to drive and I could still drive it on road trips.

Think of it like this with your 2.91 gear you are cruising 70 MPH at around 2500 to 2600 RPM and it probably isn't that good from a start. Switch to the 518 with a 3.73 gear and you can cruise 70 at around 2400 RPM and have a car that will be great from a start. It will also help you meet the goals you stated.
I'm serious considering it! I just need to get all my ducks in a row lol I'm doing a complete overhaul on my car and I'm going to rebuild the engine so it may have to come after that lol

But I did find some photos on the internet of the underneath of my Imperial and I may be okay when it comes to the frame and the transmission!

eff205c3b547ede8443f809dddcc86e5.jpg


111images.jpeg
 
G'Day All,
O.K. Please Understand I am Speaking out of Ignorance.
But 1965 was the Change over Year for the TF 727 to Sliding Yoke Setup.
As the Trans was still Operated by Cable Could the Gentleman Combine a 65 Trans & a Gear Vendors to Achieve his Desired Result?
I'm Assuming the 65 Trans was also the First Year for no Rear Pump and as such would be suitable for the GV O/D.
Also Changed to "Easy Change" Brake Drums Same Year.
Hope This Suggestion Helps.
My Advice Also, He will need to Change his Diff Ratio otherwise He will own the only Hernia Powered Car in History LOL. (22.8 Final Ratio)
I Have a G/V Setup & I'm Hoping to Run 3.73 Gears Behind a 383 4BBL, Final Drive will be Around 2.91.
Regards Tony.M
 
Well I do have some good news! Imperial services is now called Promerican Engineering and they still maintain their website. I couldn't find the kit so I emailed them... 895 for the kit or send my controls in for 595. Not terrible but I was hoping to have a "reversible option" incase I need to go back to my original transmission
 
Looks like you got all kinds of room. Just off the top of my head you will probably need to move the exhaust pipe, cut a big portion of that cross member top to make room for the OD part of the trans. Where I put the box I would weld a 1/4 to 3/8 piece of flat stock to make it strong again. The 2 pics at the bottom are mine on my 70. I had to use a piece of channel under my cross member for the trans mount stand but it looks to me that your cross member is much bigger than mine so you shouldn't have to do that.

If you are planning on pulling the engine and trans for a rebuild anyway I would buy a junk or core 518, drop that cross member out and slide the 518 in its place as a mock up. If you don't like what you see or then stick to your stock set up. I suspect it will fit pretty nicely.

1653394751227.png

1653395415054.png

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Oh one more thing before you buy the trans make sure you get a pre 1992 (I think) You want the one shown below with the 3 pin, not the bigger 5 pin. The newer trans has a electronically controlled governor and you need a computer for that. The 3 pin you just need switches for the OD and LU.
1653396377477.png
 
Mainly I was looking for a little better fuel economy on trips and in town

895 for the kit or send my controls in for 595.
Let's do the math...

You want to save fuel, and that's all cool but let's see the real cost.

Let's say you buy the $600 kit... and then buy a rebuilt trans. What do you think? $2000 all in? Maybe that's optimistic. I'm betting closer to $3k by the time everything is done, buying mounts and adding up all the "nickle and dime" stuff.

So.... Let's say you drive that Imperial about 10K miles a year. I think that's a lot, but you are in better weather year round than I am.

Let's get optimistic again and say you are going to get 20% better mileage. Probably not near that.... but whatever... and the car now gets 13MPG. A 20% increase in gas mileage gets you to 15.6 MPG.

I paid $5.25 the other day for ethanol free gas, so we'll use those numbers. 10k miles at 13MPG equals $769 spent on gas. 10k miles at 15.6 MPG equals $641 spent on gas for a $128 savings per year for gas.

So, using really optimistic numbers for gas mileage increase (20%) and optimistic numbers for the cost ($2000), it will take 15.6 years at 10k miles a year to break even even at $5.25 per gallon.

If you used some less optimistic, but more "real world" numbers of 10% mileage increase with $3000 cost, now you have 14.3 MPG and $699 cost per year so saving $70 per year. Do the math on that and it's 42.8 years before you break even.

If you only drive the Imperial 5k miles a year, double that time to break even. If gas prices go down, the savings will take longer.

This is the argument I give whenever I hear "increase fuel mileage" as a reason to throw wads of money at a car.
 
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