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engine id
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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 |