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 1969

The block is a 69 428.

Another example is:

K109 "WA"

K = October or November - 10th day - 9 = 1969

The block is a 70 455 4 bolt.

These motors usually have a large "70" at the rear of the block.

Click picture for larger view




*Note - blocks with only 2 mounting holes or pads (for the motor mounts) per side is from 1969 and older 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 certain blocks for 4 bbl carb usage have scallops in the cylinders at the deck for unshrouding the intake valves. Most 1967 and earlier blocks place these scallops at approx 4 o'clock and 8 o'clock while 1968 and newer blocks place the scallops at 3 o'clock and 6 o'clock. 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.

Here they are:

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

Click here for HEAD ID chart