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Discussion Starter #1
Does anyone know how to tell the difference between the LT1 and L99 4.3 by just looking at them? Is there something stamped on the block. Both engines look the same. Thanks
 
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Discussion Starter #2
one good way to tell is to look and see if it has duel exaust if it doesnt than its probily a 4.3
 
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You can, assuming the engine is in a car, look at the 8th digit of the vin. P= LT1 and W= L99. Also, check the little sticker on the core support with the belt routing, lists the engine size there as well. Another way, take it for a ride and mash the hell out of it! If you are pleased, it may be the L99. If you are VERY PLEASED and a bit excited, you have the LT1!
 
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Discussion Starter #4
dual exhaust is the easiset way to tell...........or else look for LT1 on the trunk lid sticker too if it still has it
 
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Discussion Starter #5
Charliess..nice to see you in this forum as well...remember:
1.dual exhaust
2.vin number "p" in 8th pos.
3.spid code has 9c1, LT1 in it
4.catalyst logo next to rad top "5.7L"

i don't think it is an L99...if the wheels can do a burn-out easily...it's an LT1
good luck..did you buy the car???
ciao
fabs
 
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Fabs, the VIN on the door and windshield are the same indicating LT1. The trunk SPID sticker says L99, non 9C1. I guess 2 out of 3 says LT1. I will buy the car after he finds another one.
 
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Discussion Starter #7
Wait!!! in the engine compartment does it have green silicone hose (NOT BLACK)? If it does, it is a 9C1 and the trunk lid was more than likely replaced, which could mean that the car was wrecked. Also our windows do not have the the vin written on them like imports.
 
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Discussion Starter #8
Charliess
The GM parts catalogue says the block code is stamped on the right front cylinder bank right in front of the cylinder head just as they've done for 30 years. I've looked at and used these codes for years on the old engines but never used it to identify LT1s. Here goes with the codes:
1994 wha whh whk whl wht
1995 xha xhb xhc xhk
1996 ysu ysw ysx ysz
 
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Discussion Starter #9
darth: can you give some more directions on finding where the codes are stamped?
 
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For a civilian Caprice, the L99 motor has a lower output alternator, 100 amps compared to the LT1's 140amp alternator. You can see the difference by looking at the alternator cooling fan. The 140amp fan has blades on the inside, like a vented brake rotor. The 100amp alternator has traditional looking fan blades. If the car is any sort of special service Caprice (9C1, 9C6, etc.) then the above does not apply. All special service Caprices got the bigger 140amp alternator.

The 8th digit VIN code for the L99 is W. The L99 was standard on both the civilian and special service Caprice. The LT1 was standard on the Caprice wagon, Impala SS, Roadmaster sedan & wagon, and the Fleetwood.

There is a machined pad on the passenger side deck surface the is not covered by the head. However, it is obscured by the alternator. That's where the codes Darth posted are located. Those codes will give you the year and displacement of the block. If the block has ever been decked, these engraved codes are usually machined off in the process.

There is also a VIN derivative located on the driver's side rear of the block, above the oil filter pad. If the engine is original, then the VIN derivative on the block will match the 3rd, and 10th through 17th digit of the car's VIN.

The L99 used two cats like the LT1, but a Y-pipe connects the driver's side to the passenger side to a single pipe with muffler and resonator.

I have been told that on the L99 block, there is 4.3 in cast raised numbers on the side of the block near the core plugs. I can't remember which side though. Kind of like 360 or 318 being cast into the driver's side of Dodge blocks. No such numbers are found on the LT1 block

I've also been told that the '96 4L60E transmission case on the L99 is two pieces, with the bell housing being bolted to the rest of it. I don't know for sure if the is just for the civilian Caprice or applies to the special service cars as well.

The best VIN locations are <UL TYPE=SQUARE><LI>On the dash visible through the windshield<LI>Federal Safety sticker on driver's door<LI>SPID label on upper left hand side of decklid[/list]

If any of these VINs do not match each other, I'd start asking some serious questions about the history of the car. Also check the underhood emissions sticker on the radiator support to see if it matches the engine codes on the SPID and the model year of the vehicle.

For LT1 Caprices the SPID should have the QMU or QMV tire codes The LT1 engine requires P235/70R-15 tires. Check tire placard on the driver's door.

The civilian L99 Caprice also has a 2.93 rear end with rear drums, code GW9. The special service L99 Caprice has a 3.23 rear end with discs on a 9C1 or drums on a 9C6, code GU5.
 
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Discussion Starter #11
<BLOCKQUOTE>quote:</font><HR>Originally posted by charliess:
Fabs, the VIN on the door and windshield are the same indicating LT1. The trunk SPID sticker says L99, non 9C1. I guess 2 out of 3 says LT1. I will buy the car after he finds another one.<HR></BLOCKQUOTE>

<BLOCKQUOTE>quote:</font><HR>Posted by Nory:
Wait!!! in the engine compartment does it have green silicone hose (NOT BLACK)? If it does, it is a 9C1 and the trunk lid was more than likely replaced, which could mean that the car was wrecked.<HR></BLOCKQUOTE>

That's a good point. If those hoses are green and there's not the "9C1" on the parts label on the underside of the trunk lid, I'd say that the trunk's been changed and don't listen to it. It's not hard to change a trunk lid if it got dented or something from throwing a suspect onto it
 
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Discussion Starter #12
<BLOCKQUOTE>quote:</font><HR>The civilian L99 Caprice also has a 2.93 rear end with rear drums <HR></BLOCKQUOTE>

so did the civilian LT1 cars like mine
 
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