Adapting 5 speed trans

39/40 Coupe

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What vehicle(s) do you drive?
1939 Ford V8, 2016 BMW 535d
Adapting a 5 speed Tremec to either 429 or 472 Cadillac
 

39/40 Coupe

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1939 Ford V8, 2016 BMW 535d
I've got an aluminum Pontiac flywheel housing and a Steel Quicktime that will fit the 5 speed if you are interested.
More info please?
Excuse my ignorance but could explain what other parts ect are reqd
Thanks and much appreciated.
JCB
 

gordon

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I already have a new after market steel flywheel, and an OEM aluminum bell housing. Found out I need to buy special bellhousing to fit the six speed magnum gearbox as the 5spd and 6 spd are not the same on front of trans. Thanks for the offer.
 

53 Studillac

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More info please?
Excuse my ignorance but could explain what other parts ect are reqd
Thanks and much appreciated.
JCB
JCB,
You will need a Cadillac specific flywheel. Normal BOP 4 speed flywheel housings will work. If you want to run a T56, there are custom flywheel housings available. I ran a TKO 600 5-speed on a stock aluminum Pontiac housing. Currently I am using a T56 Magnum with a Quick Time steel housing. The only other special thing is the trans input shaft support bearing. There are custom ones available that fit into the torque converter recess in the crank. I have always had the crankshaft machined for a standard GM bushing. You can drill the crank hole deeper but some just shorten the input shaft. The first time I mounted a tranny behind my Caddy I drilled it out with a hand drill. I didn't want to shorten the shaft on the trans in case I wanted to use it elsewhere.
 

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48Austin

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What vehicle(s) do you drive?
1964 Commercial, 1948 Austin, 58 Pan
I had seen on this forum and others that manual transmissions don't like the big Cad. I wanted to put one behind mine. Now what?
 

39/40 Coupe

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JCB,
You will need a Cadillac specific flywheel. Normal BOP 4 speed flywheel housings will work. If you want to run a T56, there are custom flywheel housings available. I ran a TKO 600 5-speed on a stock aluminum Pontiac housing. Currently I am using a T56 Magnum with a Quick Time steel housing. The only other special thing is the trans input shaft support bearing. There are custom ones available that fit into the torque converter recess in the crank. I have always had the crankshaft machined for a standard GM bushing. You can drill the crank hole deeper but some just shorten the input shaft. The first time I mounted a tranny behind my Caddy I drilled it out with a hand drill. I didn't want to shorten the shaft on the trans in case I wanted to use it elsewhere.
Thanks for your response. I have just purchased my 429 motor. I can get the adapter to a BOP or SBC from Cad500 with the flywheel ect, so I need a bell housing and clutch. How much for the bellhousing?
What clutch is best to use? JCB
 

53 Studillac

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Not sure how rowdy your cam will be but something I learned when I first ran the TKO 600 was I needed a lower gear. I was running 29.5" tall tires with 3:25 gears and when shifting into OD at normal speeds the engine would pull down too low and wasn't happy. I had a big solid roller cam and it idled around 1250 rpm. I had to run 80 mph to use OD! This go round I am running 28.4" tall rear wheels with a 3.70 gear. If your cam is closer to stock the Cadillac torque will pull you along at almost an idle.
 

gordon

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I am going with a 3:50 R&P at first and with a solid flat tappet cam that should be fairly tame. Solid Idle at 700 -750 RPM and slightly shorter tires I hope to snick into 2nd OD (.50) around 1500 rpm. I plan on keeping this thing mild mannered for extended highway trips and also not too snotty to handle traffic on a 90* day with the AC on. Hoping the Wide ratio version of the T56 magnum will help with this plan. Which version of the T56 do you have. Wide or close.
 

53 Studillac

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I have a TUET1109 purchased from American Powertrain way back in 2013! It is the close ratio version and the gear spread should be better for Cadillac torque levels. Mine has a 6th gear ratio of 0.63 and from what I see on the chart I don't think the close ratio comes with the 0.5 ratio for 6th. I'm sure it could be changed.
TUET 11009 close ratio: 1st 2.66, 2nd 1.78, 3rd 1.30, 4th 1.0, 5th 0.80, and 6th 0.63
TUET 11012: 1st 2.97, 2nd 2.10, 3rd 1.46, 4th 1.0, 5th 0.74 and 6th 0.50
 

53 Studillac

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Not sure how rowdy your cam will be but something I learned when I first ran the TKO 600 was I needed a lower gear. I was running 29.5" tall tires with 3:25 gears and when shifting into OD at normal speeds the engine would pull down too low and wasn't happy. I had a big solid roller cam and it idled around 1250 rpm. I had to run 80 mph to use OD! This go round I am running 28.4" tall rear wheels with a 3.70 gear. If your cam is closer to stock the Cadillac torque will pull you along at almost an idle.

While I was looking up which transmission I had purchased, I found where I actually have 3:89s in the rear now. It wouldn't surprise me if I end up with 3.70 or even 3.50 at some point. Below are some numbers I ran, It looks like I will need a carbon fiber driveshaft if I ever stretch her out. That 120.5" wheelbase takes a long driveshaft, which lowers the critical speed. 3:50 gears could drop cruise RPM by 200 at 75 mph.

T56 magnum gear ratios:
close ratio 1st 2nd 3rd 4th 5th 6th
2.66 1.78 1.3 1 0.8 0.63

9" Ford ratio: 3.89 3.11 2.45

OD
Rear tires: 315-35-20 28.4

MPH = (Engine RPM x Tire Diameter/Gear Ratio x 336 5800 Max Engine RPM
4th gear MPH 126.0 5800
5th gear MPH 157.5 7250 5600 Max High Gear
6th gear MPH 193.1 8889
6th gear MPH 200.0 9206 5800 Engine RPM for 200 mph
6th gear MPH 75.0 3452 2175 Cruise RPM
 
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gordon

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Yup that is quite a bit of RPM on the drive shaft. One of my big unknowns right now is tire sizes and dia. I am thinking of staying with a 17" rim and using a 255mm tire width. to keep front and back under the fenders more easily. I already have the drop out set up with new 3.50 R&P so will start with that and order the trans in a couple of months as a wide box with .50 2nd OD. Trying real hard to stay away from the wider rolling stock especially in the rear. Want the car to look more sedate. I noticed the price for the Bell housings have really gone up. Probably still go with the Quick Time bell housing instead of the non sfi aluminum unit.
 

53 Studillac

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Places like American Powertrain would custom build you a trans with the 0.5 OD ratio in 6th with the close ratio gears in 1st thru 3rd. If I ever get to run top end I might make that change to keep the RPMs down. My torque peak was 710 ft-lbs at 5000 RPM and yours may even be lower with a smaller cam. She will love a tall gear. Torque peak is You really won't need to extra ratio down low with the Cadillac torque. Is there an aluminum option for BOP with a T56? I have the plate you will need to dial in the flywheel housing when you get to it. I still have to do mine. The T56 housing has cut-outs that prevent the dial indicator from reading all the way around. So they make a precision plate that bolts up to give you a round hole to work with.

When you figure out what you want to run, I have a spreadsheet and can enter your data or send it your way if you are handy with Excel.
 

gordon

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The Aluminum one is thick walled but not sfi. costs between $495-630 depends who you buy from. Moderndriveline had cheepest price of $495 . Looks like it should work on the Caddy also. Has multiple patterns drilled, claims Olds, Pontiac, Buick applications. has dual starter pockets for OE starter locations and accommodates up to 168 tooth flywheel. I am might get this one. I think company called quickdraw makes it.
 

48Austin

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The Aluminum one is thick walled but not sfi. costs between $495-630 depends who you buy from. Moderndriveline had cheepest price of $495 . Looks like it should work on the Caddy also. Has multiple patterns drilled, claims Olds, Pontiac, Buick applications. has dual starter pockets for OE starter locations and accommodates up to 168 tooth flywheel. I am might get this one. I think company called quickdraw makes it.
If I'm not mistaken, Quickdraw is Lakewood.
 
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