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1930 Build Date Buick Straight 8 + Transmission ID

Bill Gietema

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I have a Buick "Speedster" with a 1930 build date Straight 8 engine. I have two basic initial questions:

1. How do I determine/find the size of the engine? It is stamped 13728

2. How do I identify the transmission? It has two alpha-numeric rows stamped into the housing.  

                    AS 500 186N

                    410 FAB 810 000

Oddly the transmission is currently configured as a top loader but seems to have removable side plate to allow conversion to a side loader. 


I appreciate your help and insights.

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Not sure how you know your straight 8 has a 1930 build date (it could have) but the first year for the straight 8 in cars was the 1931 model year, 50 series (221 cu in) had single barrel updraft Marvel carburetor and fuel pump is on right side of the block.  60 series (272 cu in) had 2 barrel updraft Marvel carb, fuel pump on left side of block, 2-1/4" exhaust had pipe and single disc clutch.  Series 80/90 (344 cu in) also had 2 barrel updraft Marvel carb, fuel pump on left side and dual disc clutch.  I'm 400 miles away from home and my service manuals so I'm writing this with just highlights.   The numbers on the outside of the trans are likely casting numbers, not part numbers or build dates.  If I had access to my service manuals they list some information in the specifications that might shed some light on which trans you have.  Pictures of both side of the engine, top and side of the trans would help a lot in identifying what you have.  Serial number for 31 engines (2624638-2751921) is on a flat pad above the rear lifter cover and there are lists of serial number ranges that would help verify the year. 

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7 hours ago, Coupe 31 said:


how is your 31 66s restoration going.?

My car is coming along reasonably well.  The last big projects that need to be completed are front seat upholstery and installation, rumble seat upholstery and installation, garnish molding refinish and install and hook up the fuel line from the tank.  I've carefully avoided putting fuel in the tank until the car is finished to avoid spoiled fuel.  I've been using a portable 3 gallon tank for the short runs I needed to make to get the car running correctly.  Could you post some pictures of your car?  I'd like to see what you have.



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Since the car was rebodied as a roadster, the only build number was on the engine block. This was found on the bottom left side. It is my understanding that a five digit number (13728) corresponds to a 1930 build date. We will look on the rear pad near the lifter cover. I will also post side pictures of the engine. Thank you for your help.




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Car looks great.  The body is a 1931 "Special Coupe" body judging by the headlight shape, could be 8-56S, 8-66S or 8-96S depending on the wheelbase.  Which side is the fuel pump on?   What is the number stamped on the flat pad behind oil filler neck on rear lifter cover?


My car is an 8-66S Special Coupe.



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6 minutes ago, Bill Gietema said:

Do you have any idea what the number is we found on the engine? 


"13728" This was found on the front bottom left side of the block. 

That is a casting number, not a serial number.  There may be several thousand blocks with the same casting number, only one unique serial number per engine.  Left side of block, on a machined flat pad, above the rear lifter cover. 


My 31 60 series serial number

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Country Club Coupe designation I don't believe is correct, Buick called the 8-66S a Special Coupe.  Believe it or not they built about 6,000 of this model vs about 2,000 Business Coupe models.   The wire wheels and side mounted spares are a very desirable option, wood artillery wheels with single rear mounted spare like mine.   Interesting statistics here.


Classic Car Specifications, Engine, Wheelbase, production numbers, VIN numbers for Antique Cars, Classic Cars, Vintage Cars and Muscle Cars (classiccardatabase.com)

Edited by Str8-8-Dave (see edit history)
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That is correct.  1931 and 32 50 series Buicks had the starter on the driver side of the engine and all larger sizes had the starter on the passenger side. Likewise, the fuel pump for 50 series is on the passenger side and the larger 60-80-90 series had the fuel pump on the driver side.


Bob Engle

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