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engine id

Bore & Stroke Figures

Engine
Year Produced
Bore
Stroke
326
1963-67
3.781
3.750
350
1968-77
3.875
3.750
389
1959-66
4.063
3.750
400
1967-79
4.120
3.750
421
1961-66
4.094
4.000
428
1967-69
4.120
4.000
455
1970-76
4.150
4.210
V-8 FIRING ORDER 18436572
Counter clockwise rotation

400 428 455 Engine ID

This is a quick block ID for junk yard hunting, etc. You must find the date code at the back LH side of the block first. The letter is the month, next 2 digits are the day and the last digit is the year. Here are 2 examples:
A249 code "XE"A = January - 24 is the 24th day - and 9 is 1969The block is a 69 428. Another example is:K109 "WA"K = October or November - 10th day - 9 = 1969The block is a 70 455 4 bolt.These motors usually have a large "70" at the rear of the block.
*Note:Blocks with only 2 mounting holes or pads (for the motor mount bolts) per side is from 1959 to 1969. Blocks with 5 or 3 mounting holes or pads (for the motor mounts) per side is from 1970 and newer. Blocks with 2 freeze plugs per side is 1966 and older.Blocks with 3 freeze plugs per side is 1967 and newer.Most high compression (1970 and older) blocks have scallops in the cylinders at the deck for unshrouding the intake valves.Most 1967 and earlier blocks place these scallops at approximately 4 o'clock and 8 o'clock while 1968 and newer blocks place the scallops at 3 o'clock and 6 o'clock. Some early 2 bbl blocks and most newer blocks did not have any scallops.
400

67 400 FULLSIZE:
XA XB WA WB WM WN YA YB YC XV YD XU YU YV XC YE XW YF XX YX WD XT WE WY XY XZ YL XH XJ WF
67 GTO 400:
XM XL WT WW YS XE WS WV YZ YI (RAM AIR) XS YR XP
67 FIREBIRD:
WZ WU YT (RAM AIR) WQ XN WI
68 FULLSIZE:
YA XA WA WB YC ZR YE YF XZ XH
68 GTO
XM WT YS (400 HO) WS YZ (RA I) XS XP (RA II) WY XW
68 FIREBIRD:
WZ YT (400 HO) WQ YW (RA I) WI XN (RA II) WU XT
69 FULLSIZE:
WA WD YA YB WB WE YC YD XZ WX XH YF 69 GTO WT YS XM XX (RA III) WS YZ (RA IV) WW XP
69 FIREBIRD:
WZ YT (RA III) WQ YW (RA III) WH XN
70 FULLSIZE:
WE YD YB XZ WX XH
70 GTO & FIREBIRD:
XX XV WT YS (RA III) WS YZ (RA IV) WW XP
71 FULLSIZE:
WS XX YS
71 GTO, GP & FIREBIRD:
XX WT WK YS
72 ALL:
YX YZ ZX WS WK YS YT
73 ALL:
YP ZK Y4 YX Y1 ZX YZ YT XK ZN WS YF WP Y6 YG YN ZS YY XX X5 Y3 YS XN
77-79 TA 6.6 (W72 option)
casting number 481988 XX is cast on the valley area and externally
428

67
WG YY YH Y2 XD WJ XK YK Y3
68
WG YH WJ YK
69
YL YH WG XK XE XJ WJ YK WF XF WL XG
455

70 FULLSIZE:
YH - 2 BOLT WG XF - 4 BOLT
70 GTO:
WA YA YC - 4 BOLT
71 FULLSIZE:
WJ YC WG YG - 2 BOLT
71 OTHERS:
HO (4 BOLT) WL WC YE
72:
2 BOLT YH YC YA ZH
72:
4 BOLT (HO) WM YB WD YE
73:
YK X7 YD XM WW WT YC XE YA XL ZC ZA (SD) ZJ XD
74:
Y9 Y4 Y6 A4 Z4 Z6 YY YU YX AU ZU ZX YW ZW YR (SD) W8 Y8
75:
YW YU ZU ZW WX
76:
Y3 Y4 Z3 Z4 Y8 ZB WX
Service Replacement (SR) blocks do not always have a code stamped on the front of the engine. They do, however, usually have a casting number. This casting number is usually on the RH side of the rear portion of the block - where the transmission bolts up.
400 Castings

67
9786133
68
9790071
68 Ram Air
9792506
69
9790071
69 Ram Air IV
9792506
70
9799914
70 RA IV
9799915
71 to 74
481988
75
488986 (early) 500557 (late)
76
500557
77 to 79
568557
78 to 79 (TA 6.6)
481988 xx
428 Castings

67
9786135
68 & 69
9792968
455 Castings

70
9799140
71
483677 (early) 485428 (late)
72 to 74
485428
73 & 74 Super Duty
490132
75 & 76
500813
Head Id Chart
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