455 SD Facts and numbers:

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FACT 1: The '73 and '74 Super Duty cars had the SAME engine rated at 290 bhp .... the 310bhp were never sold to the public.

FACT 2: The top two bolts of the valve cover AND also some of the rocker studs, unless threads are sealed will suck oil  into the intake manifold and burnt in the motor.

FACT 3: The valve springs have a different installed height on the SD as opposed to "other" Pontiac motors.

FACT 4: The following SD parts were different from your "average" Pontiac .... Block, Heads, Con Rods, Con rod bolts, Pistons, Valve Springs, Valves, Intake manifold, Cam, Distributor, Carburetor, Oil pump, PCV valve location.

FACT 5: The intake valves on the SD have a 45 degree seat angle. Nearly all other Pontiacs had 30 degree seat angles on the intake valves. The exhaust were common with other Pontiacs having 45 degree seat angle.

 

 

 

VIN Number :

The 5th digit will be an 'X'

 

Block ID :

Cast on the rear of the block 490132 - 491948

Stamped on the front of the block:

1973 auto XD

1973 manual ZJ

1974 auto Y8

1974 manual W8.

Pontiac have been known to mis-stamp on a few occasions e.g. my old '73 SD T/A auto had its block stamped XJ.

Reinforced lifter valley webbing.

Provision for Dry sump oiling.

4 bolt mains.

 

Head ID :

485214 - 485216

Cast on centre exhaust port is a number 16. A small number of heads did not have this number cast.

On a small machined surface just below the valve cover the  digits 6H will be stamped.

id01.JPG (52952 bytes)      id02.JPG (41017 bytes)      

Screw in studs.

Press in push rod guides.

2.11 Intake valves with 45 degree seats and 1.77 Exhaust valves with 45 degree seats.

 

Rods :

485225

Forged SAE 8640 steel.

Series A,B,C,D,E,F,G and H.

7/16 inch bolts.

Rockwell 25-32.

 

Crank :

490164 - 9799103 - 495030

Nodular Iron.

 

Pistons :

493159 - 493163 - 493421

TRW forged. These Pistons only fit the SD rods.

 

Camshaft :

493323 'Y' - 0.401inch lift or is it 0.407 inch lift ?

310 degree exhaust duration - 298 degree intake duration (Pontiac info).

313 degree exhaust duration - 301 degree intake duration (Other non-Pontiac sources).

 

Intake ID :

Cast here will be either LS2 or LS2X.

Also stamped are one of the numbers 494419 - 495107 - 495103 - 494405.

id01.JPG (52952 bytes)

 

Exhaust ID :

490803 - Left.

490802 - Right.

Round Port.

 

Carburetor ID :

Rochester Quadrajet 800 cfm

1973 - Automatic 7043270

1974 - Automatic 7044270

1973 - Manual 7043273

1974 - Manual 7044273

GM service replacement for auto 17054819

 

Distributor ID :

1112205

Large distributor gear.

 

Other ID :

The nearside valve cover has a red and silver Superduty 455 decal.   The PCV valve is positioned in the oil filler cap instead of the usual valley cover.

id03.JPG (35179 bytes)

 

TRANSMISSION

 

TH400 : SD code PQ followed by serial number eg. mine is 74 PQ 1296

 

800 cfm QuadraJet  Jetting

The data below is the stock factory specification

 

Automatic Transmission 

1973 - 7043270

1974 - 7044270

Factory Service Replacement - 17054910

Manual Transmission 

1973 - 7043273

1974 - 7044273

Primary Jets 75 74
Primary Rods 49 44B
Secondary Rods BV DM
Power Spring