Identification, VIN, Trim, Engine Specs and more... 
 '50   '51   '52   '53   '54   '55   '56   '57   '58   '59   o 
 p 
 e 
 n 
 '60   '61   '62   '63   '64   '65   '66   '67   '68   '69 
 '70   '71   '72   '73   '74   '75   '76   '77   '78   '79 
Canadian car identification here: Serial Numbers 1935-1964 | 1965-1966
and more information in the reference section here.
Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: 1966 Buick GS 401 Engine

  1. #1

    Question 1966 Buick GS 401 Engine

    I just purchased a 1966 Buick gs 400 and have some questions regarding engine codes. My engine is stamped MFR(the F could be T stamped twice) space W340 and my protect-o-plate engine code is stamped MR340. Can someone tell me what these codes mean? I know that there were a couple of rare 66 gs made that year and am not sure if my car is the one with 340 horsepower?

  2. #2
    The engine stamping should match the protectoplate: MR340. MR is the code for the standard 10.25 compression 4bbl 400 (401) for the 66 Gran Sport Skylark. 340 is some sort of date code I can not decode, but these engines came with that three number code after the engine code.
    Steve B.



    67 GS 525 Buick Stage IV
    66 GS Convertible
    65 GS HT
    63 Riv
    02 Subaru WRX Turbo
    03 Ford Cobra Convertible (Factory Supercharged)

  3. #3
    I believe the 3 engine codes for the '66 GS's were MR/325HP MT/340HP & MU/356HP

    Tom T.

  4. #4

    1966 Buick GS 401

    Thank your for your response.
    James J Buscemi
    1970 Buick GS Stage One 455
    1969 Buick GS Stage One Convertible 4 Speed (Rare)
    1969 Buick GS 400
    1968 Buick GS California
    1970 Buick GS 350
    1966 Buick GS 401

  5. #5
    Correction, MT is a 401 in a regular car, not a GS. The correct code is MS/340HP.

    Tom

  6. #6
    Here's out site reference for the '66 engines...

    http://www.buicks.net/shop/reference...ent_63_75.html

    It does not show the MS option, but it does agree with buscemi32 that his MR 340 is correct for his car.

    Our reference doesn't show the MU option. Do you have any more information about it?
    If you would llike to place an image of your car in your signature, click here for instructions
    WEBNOTE: When inserting an email in a posting, use the "smilie" @ so that web robots don't pick up your address and send you more junk mail!
    Members can be contacted by clicking on their "handle", but you are much better off to post to the thread!

  7. #7
    Bob,

    My Buick dealer bulletin book lists the codes and a little information on the 66 400 (401) engines. I have:

    MR - 400, 4 bbl, 10.25 to 1
    MS - 400, 4 bbl, 11 to 1
    MU - 400, 4 bbl, 10.25 to 1
    MT - 401, 4 bbl, 10.25 to 1
    MY - 401, 4 bbl, 8.75 to 1 (export low compression)

    The 66 Buick CSM lists:

    MR - 400, 4 bbl, 10.25 to 1
    MT - 401, 4 bbl, 10.25 to 1
    MV - 401, 4 bbl, 8.75 to 1 (export low compression)

    I think one of the export codes was transposed (most likely MY as the CSM has the MV listed in several places), but I have never seen an export to confirm.
    Last edited by Dr. Frankenbuick; 08-11-2006 at 09:31 AM.
    Steve B.



    67 GS 525 Buick Stage IV
    66 GS Convertible
    65 GS HT
    63 Riv
    02 Subaru WRX Turbo
    03 Ford Cobra Convertible (Factory Supercharged)

  8. #8

    More info 1966 buick gs 401

    vin plate codes
    02D 3475
    66-44617 KAN-1398
    167-C R-C
    WO 2XR 4C 5KY

    ENGINE STAMP MFR or MTR W340 K12 434

    Complete Protect-o-plate codes
    167-RC 446176K122434
    MR340
    NK132D 148

    Barr Buick CO 12-389
    1204 Main Street Buick
    Vincennes, IND

    Parker & Son 12-389
    8 N 1st St 4-21-6 4N
    Vincennes, IND 6K122434
    James J Buscemi
    1970 Buick GS Stage One 455
    1969 Buick GS Stage One Convertible 4 Speed (Rare)
    1969 Buick GS 400
    1968 Buick GS California
    1970 Buick GS 350
    1966 Buick GS 401

  9. #9
    I will decode what I can for you:

    02D = build date = February 1966, fourth week
    66 = model year = 1966
    44617 = Body type = 4 - Buick, 46 - Gran Sport, 17 - 2door HT Coupe
    KAN = assembly plant = Kannsas City, MO
    1398 = unit # = 1398
    167-C = seat code = notch vinyl bench, two tone red
    R-C = color code = R - flame red lower body color, C - artic white top? (paint or vinyl)
    WO 2XR 4C 5KY = unknown to me

    ENGINE STAMP MFR or MTR W340 - Should be: MR340 - GS 400 4bbl 10.25 compression engine and the date code. There may have been some double stamping.
    K12 434 - Should be: 6K122434 the last 8 digits of the vin # stamped on the block.

    Complete Protect-o-plate codes -
    167 = notched vinyl two tone red seats (again)
    RC = Paint codes Red and white (again)
    446176K122434 = vin# (found in drivers door opening) 4= Buick, 46=GS, 17= 2 Dr HT, 6=1966, K= KC, MO Assembly plant, 122434= sequential build nuber of the line.
    MR340 = Engine code (as described above)
    NK132D = Transmission code (stamped on servo cover), NK=1966 GS ST300 transmission and 132D is a date code.
    148= I can not decode that.

    HTH
    Last edited by Dr. Frankenbuick; 08-17-2006 at 07:06 AM.
    Steve B.



    67 GS 525 Buick Stage IV
    66 GS Convertible
    65 GS HT
    63 Riv
    02 Subaru WRX Turbo
    03 Ford Cobra Convertible (Factory Supercharged)

  10. #10
    So, MR MT & MU were only available in the GS400 or were they in other models too?
    If you would llike to place an image of your car in your signature, click here for instructions
    WEBNOTE: When inserting an email in a posting, use the "smilie" @ so that web robots don't pick up your address and send you more junk mail!
    Members can be contacted by clicking on their "handle", but you are much better off to post to the thread!

Similar Threads

  1. 1966 Skylark engine swaps
    By 455Schilf in forum Engine and Transmission Swaps
    Replies: 6
    Last Post: 09-14-2009, 07:19 PM
  2. 1966 Buick Riviera GS : Wrong engine and carb ?
    By bertrandboss in forum Nailhead: 264, 322, 364, 401, 425
    Replies: 12
    Last Post: 09-01-2009, 04:31 PM
  3. 1966 Buick Riviera 425 Engine Info
    By BluesBrothersBuicks in forum Nailhead: 264, 322, 364, 401, 425
    Replies: 9
    Last Post: 12-08-2008, 03:35 PM
  4. 1966 300 Buick engine exhaust manifold
    By Edensw in forum Restoration Talk
    Replies: 0
    Last Post: 12-28-2005, 06:13 PM
  5. 1966 401 Engine Parts
    By BeechedOut in forum Restoration Talk
    Replies: 1
    Last Post: 08-12-2005, 12:22 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
TeamBuick.com Privacy Policy