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Discussion Starter #1
I read on another post that when you are in question if you have the 4.3 or the 5.7 in your 96 Caprice that "327" is cast into the block, but where at in the block is it cast? According to my VIN# I have the 4.3L but, my engine goes through gas around the same amount that my buddy's 350 5.7 does...

Which brings me to my next set of confusion... According to the paperwork I got with my Caprice when I purchased it, the paperwork says 5.7L V8 which in turn if it's the 5.7L that would mean it has the 350 in it right? But when I say 4.3L on the top of my radiator, now I question if a LT-1 swap was done in it or not. And another thing that is weird to me s that I have Dual Exhaust, STOCK Dual's, I thought the 4.3 came with Single Exhaust on the passenger side?

Also, I wonder now how common the 5.7L was, because on the AutoParts website it says the 5.7L is found in over 70% of 1996 Caprices. Any help would be greatly appreciated, before I waste a trip to the strip and look like a fool. :)
 

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whats your VIN number? check your driver door,lower driver side windshield and compare the vin number. Then give us/me your vin number
 

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Discussion Starter #3
What am I comparing my VIN# too though?

VIN#: 1G1B152W7TR193870

And yes, I am aware that the "W" is supposed to mean 4.3, but like I said about the kids bodywork and whatnot he had done it says 5.7L on the papers, but my according to my VIN# it's the 4.3.
 

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4.3 is single exhaust, 5.7 is dual exhaust.

I have read of a test you can do.

From a stop sign/light push the pedal all the way to the floor and see what happens. The supposed difference is that the LT1 will put you firmly into the seat and the L99 will move but not as strong.
 

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Discussion Starter #5
If that's the case then I must have the LT-1, I mean I can feel the power behind the pedal, even my Cop friend John, said that my car is to powerful to have the smaller 4.3 in it, and this baby purrs, but is it at all possible that the 4.3 came with Dual Exhaust stock? I mean me and John pulled my Pipes off and it's all stock all the way up and all the way down, even past my CAT's.
 

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Discussion Starter #7
So is it possible that maybe I was just seeing something wrong on the radiator sticker? Or does it always say 4.3L on the sticker that's right on top of the radiator?
 

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Well your car Vin does indicate that the original engine was the L99, but your paper work that came with the car shows that the LT1 is in it now. I would believe that whom ever did the swap did not change the emission sticker (which would be illegal to do I believe) or which ever the sticker is that is on the radiator.
 

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Discussion Starter #9 (Edited)
SO should I just believe I have the LT-1 in it? And not worry to much about it? By the way:

1. I love your Impala (Kickin' it Old SCHOOL!)

and

2, thank you for responding so quickly.

Also, there is a little white sticker on the front of my engine, I seen some digits on it, but didn't write them down, and I also read somewhere about "327" being cast right into the block, where at on the block is it at? On the front of the block, the side, the back?
 

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George Bates Automotive may have that answer for you about where the 327 is stamped at. My understanding is that both engines may have the 327 stamp.:confused:

Does sound like you have the LT1 in it.

On my Impy it is old school but hopefully some day it will be an "Old School-Ultimate Sleeper", I hope anyway.
 

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Discussion Starter #11
That Impala would make a beasty sleeper bro, I'm gonna do an engine clean-up tomorrow afternoon so maybe when I am taking some older things off (Home Plate) and cleaning them, maybe I will find something worthwhile. :) But once again, thank you very much for the quick responses and for being so helpful.
 

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The usual place to look for "327" on an LT1 is on the driver's side.

It is found on L99s in other places.

If you can look behind the driver's side head it will say 4300 or 5700, little more foolproof.

Far as the exhaust thing, the L99 got dual cats, REALLY easy to go back and add dual exhaust to them. Even rumors it was an option.

LT-1 is a early 70s engine, LT1 is the 90s engine.

Far as all your worry about VIN, and emmisions sticker and everything else, it is a 13yo car, god only knows what has been done too it in that time. Get a mirror, look behind the head. You could pull the driver's side valve cover and look at the head casting number, that would be really easy too. But there are some IDIOTS out there who claim the LT1 and L99 heads are the same, here is a picture though and you can clearly see the smaller bore on the L99 head.
 

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Discussion Starter #13
Thank you very much for that information buddy. I guess it's time to tear her apart today. :smile:
 

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With a mirror and flashlight or maybe even just a digital camera you should be able to see the 5700 behind the driver's side head.
 
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