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ailimac

1947 Buick Engine Interchange

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New to the forum. Can anyone help me. I have a 1947 Buick Special Sedanette Series 40, 1947 Mod 46-s, Style No 47-4407, Body No G 759, Trim No 50, 248ci Straight Eight. I have pulled the engine and trans and was planning on having it rebuilt as the car has not run in many years. I came across a straight eight for sale on ebay (item #230911355307) from a 1951 Buick Roadmaster. My question is, can I use this motor and trans in my 47. I've been trying to get more specifics from the seller, ie engine number and size, but he hasn't replied. And while I'm asking, can someone also tell me what years engines (and trannys for that matter) I can use as a replacement in this 47, without major modifications and staying as close to original as possible.

I've searched the internet for some kind of interchange info but haven't found anything. Any other info you think would help me out would be greatly appreciate.

Thanks.

Pete

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Roadmaster will be 320 ci (longer) and probably for Dynaflow. Will not fit your special (248 ci)

Any 248-263 [1947-1952?] engine for standard transmission will swap without much trouble,

Dynaflow engine have a different crankshaft from memory (anyone else comment more accurately?)

I assume your engine has the front engine mount on the side (not front plate) I keep forgetting when engine mount design was changed

Edited by 1939_buick (see edit history)

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Pete. welcome to the Forums.

First answer, no the Roadmaster engine will not fit. It is several inches longer. All 248 ci from I believe, 1938 through the last 248 in 1950 will work, as well as the 263 from 1950 to 1953, which was the last straight eight. These will be from a

Special or a Super.

I believe probably the tranny from 1940 till '53 ill work, but don't hold me to that.

What part of the world do you hale from? And come here often. We straight eight guys need all the company we can get.

Ben

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Thanks guys. My mounts for engine are in front.

I'm located in Northeast PA in the Poconos.

I promise you'll be seeing a lot of me here in the future. My last project was a 36 Dodge and this is my first Buick.

Thanks again for the information.

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What if I replaced the 1947 motor and manual trans with the 1952 motor and auto trans. Do you know if they will fit? Will I need and modifications to drive shaft or motor mounts?

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The 52 motor and tranny will not leave you enough room between the radiator and cowl section. That is why the Roadmasters are longer in the fenders and hood. They needed the space for the extra length in the motor. It just won't fit, unless you could possibly remove everything off of the front of the motor and run electric fans??? As far as the tranny, that's a whole 'nother can of worms. Matt

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What if I replaced the 1947 motor and manual trans with the 1952 motor and auto trans. Do you know if they will fit? Will I need and modifications to drive shaft or motor mounts?
The 52 motor and tranny will not leave you enough room between the radiator and cowl section. That is why the Roadmasters are longer in the fenders and hood

From the other forum 1947 to 1952 Engine Swap

"I got some advice from another forum and was told I can use any 263 straight 8 from 1947 to 1952. So when I came across a running 1952 263 engine I bought it (stamped engine ID 56094594, casting number 13880207)"

Alimac has been given some very good technical advise on the swap. He has a 52 engine now. Not the 51 Roadmaster engine referred to in post 1

Edited by 1939_buick (see edit history)

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I have decided to use the 52 engine with the 47 manual 3 speed and find/or have made the pilot bearing/bushing that will be needed - based on advice from some people who have already did this.

My only concern is removing the harmonic balancer from the 52 motor to install the front motor mount bracket from the 47. I am assuming that the balancer will come off a lot easier then the one on the 47 did. The 47 had been sitting in the Minnesota weather for who knows how long. It took me about 8 hours on and off of pushing and pulling until finally it poppped off but by then it was totally deformed. The new motor only has 39K on it so I'm hoping it comes off easier and for that matter the timing chain spocket also because the motor mount plate sits under that.

No one has mentioned if the clutch and pressure plate will bolt to the fly wheel on the 52. I guess I'll find out soon enough.

Pete

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