455 SD Facts and numbers:
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.
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.
Forged SAE 8640 steel.
Series A,B,C,D,E,F,G and H.
7/16 inch bolts.
490164 - 9799103 - 495030
493159 - 493163 - 493421
TRW forged. These Pistons only fit the SD rods.
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.
Exhaust ID :
490803 - Left.
490802 - Right.
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 :
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.
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
1973 - 7043270
1974 - 7044270
Factory Service Replacement - 17054910
1973 - 7043273
1974 - 7044273