Author Topic: Will TH400 bolt to a 390 or 429 block?  (Read 2547 times)

Mike D #19390

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Will TH400 bolt to a 390 or 429 block?
« on: March 07, 2005, 04:13:03 PM »
Anyone happen to be familar with trans bolt patterns?

Question - will a standard BOPC pattern TH400 (probably 1968 and on to avoid switch pitch trans) bolt up to the earlier 390 or 429 blocks?  Specifically, want to replace the Jetaway in a 1960 with 390 engine with a TH400. Also have a 64 with a 429 that has the early TH400 trans, but would like to replace it with a later year trans.

(Reason for avoiding the switch pitchs is theyre real expensive to rebuilt vs. a standard TH400.  Also easier to grab a std TH400 from a junkyard.)

Michael Stamps 19507

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Re: Will TH400 bolt to a 390 or 429 block?
« Reply #1 on: March 07, 2005, 05:54:06 PM »
I wouldnt say real expensive to rebuild.  Drag guys love the switch pitch so parts are available.  That said Im sure you can get an adapter to do the swap just dont know where.  Ive been told there is an adapter made for just about everything.

Stampie

Lynn 10923

  • Guest
Re: Will TH400 bolt to a 390 or 429 block?
« Reply #2 on: March 07, 2005, 06:03:11 PM »
In a word, no. The 65 - 67 Cadillac 429 has its own transmission bellhousing pattern, not shared with any other years or cars. The 64 Cadillac bolt pattern is different again, and I dont know what the earlier engines have. The simplest option is going to be to rebuild what you have.

Lynn

Bruce Reynolds # 18992

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Re: Will TH400 bolt to a 390 or 429 block?
« Reply #3 on: March 07, 2005, 06:10:43 PM »
Mike,

Firstly, which 390 or 429 motor are we referring to?

If it is the later 429, then they used a TH400 anyway, and I am sure that the Switch-Pitch TH400 can be swapped for a normal TH400.

But, if it is the earlier 390s, then the swap you are talking about isnt a simple bolt-up exercise.

You see, firstly, the bellhousing on the 390 is round, and the later Cadillac is "odd-shaped"

Next, the starter on the 390 bolts to the bellhousing, whereas the Starter for the TH400 bolts up to the block.

The 390 has the ring gear attached to the torque converter, whereas the engines using the TH400 utilise a normal flexplate.

Any Adaptor will have to have the starter mount, as I am not sure if the 390 block can be converted to mount the starter on to the base of the block.

Having said all the above, nothing is impossible, but miracles take longer.

Hope this helps a bit.

Bruce,
The Tassie Devil(le),
60 CDV

john k

  • Guest
Re: YES it will
« Reply #4 on: March 07, 2005, 09:26:02 PM »
I hate to rain on anyones parade but IO have paired a TH400 with a 390 and early 429. The biggest hurdle is the pilot of the crankshaft on a 390 and early 429. The 390 pilot hole is smaller than the pilot nub(/) of the TH400 torque converter. However, I got around this with 2 different approaches. My first try had me widen the interior hole of a TH400 flywheel and then I had a trans rebuilder machine down the torque converter until the pilot nub fir into the 390 crank end. The 2nd try I decided to machine the 390 crank IN-CAR!!

Now, that is not the end of the story. Even though the TH400 will bolt right up to the 390, you have to use the spacer ring that came with the later 429 and TH400. You also have to use the 3-bolt starter, the TH400 sfift linkage from the steering column and carb. You also have to use the TH400 pivot linkage that bolts to the frame. You also have to use the vacuum port at the rear of a carb on a TH400 car and run a line to the TH400 vacuum modulator. The rear support, the side tranny supports and everything else bolts right up. Now dont anyone try to tell me different because I did this with 2 different 64 Cad hearses, so I know what I am talking about.



john k

  • Guest
I think I mis-read the question. Sorry.
« Reply #5 on: March 07, 2005, 09:31:21 PM »
I think I mis-read the question. Sorry for my response

Bruce Reynolds # 18992

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No need to apologise
« Reply #6 on: March 07, 2005, 10:40:28 PM »
Thats okay John,

We all have trouble at times.

Welcome to the club.   The old timers part, that is.

The best thing is that you can read, ha ha.

Bruce,
The Tassie Devil(le),
60 CDV

Ed Dougher

  • Guest
Re: Will TH400 bolt to a 390 or 429 block?
« Reply #7 on: March 08, 2005, 08:31:09 AM »
I cant speak to the bolt patterns, but I can offer this:

1967 models have 429 engines and turbohydramatic transmissions with variable pitch vanes in the torque converter.  Its featured in the sales literature.

In 64, Series 62 cars got the hydramatic.  DeVille and higher models received the new turbohydramatic.

Mike D #19390

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What a wealth of knowledge you guys are!
« Reply #8 on: March 09, 2005, 10:39:01 AM »
Thanks for all the info!  Heres a little clarification on my part.  

My 64 is a Coupe Deville, so it already has a TH400.  However, believe it or not, I occasionally drag race it, and I cant hold it in 2nd gear.  Shifts into 3rd too soon (when its floored).  The car is stock, runs around 16 flat 1/4 mile, but its fun.  My plan was to get another TH400 from a later year, rebuild it, use a little higer stall converter, and swap it in.

The TH400 behind a 390 - A member of my local club has a 60 coupe and hes very interested in replacing the trans in his car with a TH400. Several other club members with 59s expressed interest, so I thought Id float the question to the Cadillac Knowledge gurus!   Thank you everyone for the detailed replies!

Last year the switch pitch in my 67 Deville gave out, and a rebuild with new converter ended up costing $1500. If theres a next time, Ill get get a plan old BOPC TH400 and have it rebuilt.

David #19063

  • Guest
Trans shift rpm adjustments question?
« Reply #9 on: March 09, 2005, 11:27:38 AM »
Hello Mike,

I think there are adjustments you can make on the trans to change the shift points, a vacuum modulator or govenor or something that will help you.

Hopefully, someone will volunter this info.

On the pair of 68s Cadillacs I had, 1-2 shift was a little early for me, but 2-3 was very early it seemed.  I took to manually shifting it when I ran my 68 Brougham at the drag strip.

Does manually shifting make a difference for you?

Write down here the entire timeslip from your best time, it would be interesting to see.

Next time you need a switch pitch rebuilt, check out Postons in Alabama.  Buick racers are very big into the switch pitch for racing.  Get a catalogue from them, they are big into rebuilding street and performance switch pitch and non-switch pitch trans.

http://www.postonbuick.com/

David

Lynn 10923

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Re: What a wealth of knowledge you guys are!
« Reply #10 on: March 09, 2005, 12:04:44 PM »
Check closely what transmission you pick up for next time. The common BOP bolt pattern wont fit your 67 either. The 65 to 67s have a bolt pattern all their own.

Check your downshift switch to see if its working or adjusted properly. It sounds like it is not. That will make one shift up too early. If the pedal is on the floor, it should hold second gear up to around 70 mph.

A fee of $1500 to rebuild a TH400 transmission sounds extremely high. Theres a local shop near me, well known in this area with an excellent reputation, ie. probably the most expensive place around here, that will rebuild a TH400 for $400, including the convertor. Thats if I take the thing in and they dont have to remove it from the car and reinstall it. Thats also a non S/P TH400. But good grief. A S/P trans just shouldnt be that different in price. There just isnt that much different inside.

Lynn

Mike #19861

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Re: What a wealth of knowledge you guys are!
« Reply #11 on: March 09, 2005, 03:42:34 PM »

 Yes, those shift points are low. Adjust the kickdown switch for starters. My 70 Flleetwood upshifts to seconf at 50-55 mph and into 3rd at 80-85. Almost too high, but when it grabs the next gear, it just launcehes.

 Carefull of the high stall convertor bug. These engines work better at a lower RPM where they make all their torque. A high stall convertor would put the engine out of its power band, and make normal driving a bear.

  Mike

Mike D #19390

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Pics of 64 drag racing and timeslip
« Reply #12 on: March 09, 2005, 10:21:15 PM »
For laughs, here are some pictures of me drag racing the 64 Coupe, a timeslip, and my license plate (which the DMV has since revoked!)

http://www.wmsbrg.com/cadillac/Richmond/images/64_Cadillac_Drags/

Bruce Reynolds # 18992

  • Guest
Re: Pics of 64 drag racing and timeslip
« Reply #13 on: March 09, 2005, 10:28:20 PM »
Well, fancy giving out that plate in the first place.

Bruce,
The Tassie Devil(le),
60 CDV

David #19063

  • Guest
Re: Pics of 64 drag racing and timeslip
« Reply #14 on: March 10, 2005, 05:24:44 PM »
Hey Mike,

Your pictures of your 64 CDV look so cool at the drag strip!!!

David

Offline Ben H.

  • Posts: 3
Re: Will TH400 bolt to a 390 or 429 block?
« Reply #15 on: October 21, 2008, 03:25:11 PM »
I saw a similar thread in another section but will ask this here too:
Lemme see if I am learning this correctly.

I have a 63 commercial chassis. If I want to put in a trans from a 64 I need to use one from a Ser. 75 and not a Fleetwood?

I found both a 64 Series 75 and a Fleetwood at a pick n pull. I need to know what I should grab from either car. Both are really picked apart, and the engine is already gone from the Fleetwood.



Offline Chris McBride

  • Posts: 43
Re: Will TH400 bolt to a 390 or 429 block?
« Reply #16 on: October 22, 2008, 06:51:33 AM »
re: The TH400 behind a 390

http://www.wilcap.com/ indicates that it has an adapter and parts for grafting a TH400 to a 390.  http://www.wilcap.com/CAD3502.PDF

However, your shift indicator would also require modification and I have no idea what other gremlins might be involved with the linkage, et cet.

re: Ben's question that I have a 63 commercial chassis. "If I want to put in a trans from a 64 I need to use one from a Ser. 75 and not a Fleetwood?"

The 1964 Fleetwood would have a TH400 not a Hydramatic; the crankshafts are different in the two years so you would have to overcome the issues which John K discussed. I believe that the Series 75 would have a Hydramatic and probably be a more likely candidate for an easy transplant.   One of the knowledgeable vendors at the 1963 1964 Cadillac Community once had a 1963 commercial chassis Hydramatic for sale.  He alluded that the commercial chassis Hydramatic had some beefier components than the ordinary passenger car Hydramatic.

The 1964 was the first year for use of the TurboHydramatic and it has a number of factors which make it unique.  If nothing else, the switch to the perimeter frame in 1965 from the prior years' x-frame probably made the mounting brackets and other such matters different.  I know the 1964 TurboHydramatic has a unique adapter/spacer between the engine and the transmission which I don't believe the subsequent years used.  I have a vague recollection that the length of the tailshaft assembly of the model years may vary.  So, it would seem additional research is probably required to get a definitive answer.

The archives at the 1963 1964 Cadillac Community http://groups.msn.com/196364CadillacCommunity/ has several discussions concerning the crankshaft, transplant, and compatibility issues which John K mentioned. 

HTH

Chris


« Last Edit: October 22, 2008, 06:53:23 AM by Chris McBride »

Offline Ben H.

  • Posts: 3
Re: Will TH400 bolt to a 390 or 429 block?
« Reply #17 on: October 22, 2008, 02:05:37 PM »
Ok, so I am going to go for the trans out of the 64 Series 75. I should also grap the wheels and mayber steering rack goodies. This yard has $70 transmission specials, I just don't wanna shovel out $1500 on a hydramatic rebuild that wont fit my 63 cc.

 



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