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· Registered
2 Posts
Discussion Starter · #1 ·
Have a motor that i inherited need to know what it is
Gm 5.7lg sgi
Has a big 5 sideways just below 10243880 and above the 5.7
Motor was a factory pull before marriage to body is complete with alt and all wiring manifolds etc.
On valve covers marked WO31F126(may be a G) AD PRO (written with marker)
On side just above exhaust manifold stamped gm1255003
Motor is probably 1990-2004
Engine on shipping pallet yet

Thanks for any info

· More for Less Racer
22,078 Posts
It's a 350, the 880 block(10243880) is a 1-piece rear main seal and roller cam compatible block. You are likely correct about the year range

To know more we need the head casting #"s which are on the heads under the valvecover area, and the stamped application code which is on a rectangular pad just forward of the passenger side head, facing up.

The other numbers don't mean anything I can decipher.

· Registered
2 Posts
Discussion Starter · #4 ·
Additional info

Pad on passenger frt side below head behind alternato bracket is blank
Casting numbers on heads are 10239906
On a paper tag on drvers side just above oil pan is following info
CAM Green STL 10XNF V802030864
On exhaust manifolds are GM12555002LH11 ( RH on other side)
On passenger valve cover is 30ME02B W031F126AD PRO
On driver side is W031F126AD PRO These are wriiten in blue paint marker
On various parts ( like ends of valve covers, oil pan) are paper stickers marked XNF with a time code like 10:10 or some number similar in small print
Based on working in a Gm stamping plant those stickers are what plant assembled the engine and what week ( week 34 of 52) and time
The CAM could be the Canadian Assembly.

· Cars, Trucks, Boats, Motorcycl
8,402 Posts
X 2... BING BING BING... You win the prize... best engine it could be... Gen. 1.5 truck engine... most powerful potential SBC heads ever offered on a vehicle, car or truck... support up to 425 - 450 HP... does it have the TBI?

Roller lifters/cam... 9.4:1 compression ratio... great MPG... here's the long block of it:

· Wrench Turner
5,060 Posts
These motors only came in trucks, vans,& SUV's.They were not tbi motors.They used central sequential fuel injection, (CSFI)except for some 96 model heavy duty applications which used the GM Vortec to TBI intake & pre 96 system.
Net HP ratings as installed in a production vehicle is 255 HP & 330 ft/lb torque. This with all accessories, stock exhaust,&factory tuning.With a good intake,4 bbl carb & long tube headers, this is a 300 HP motor.
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