i'm thinking about buying a lt1 engine off of craigslist but i'm concerned that it may be a l99. i don't have an extensive knowledge on lt engines but the one i'm looking at appears to be a 350. my question is is there an easy way to tell the two engines apart. i'm buying the engine so and markings/castings or physical differences is what i'll be looking for.(can't go strip down the engine)
thanks!

 

Not sure how credible this is or if it's accurate, but I've read(not personally checked) that the LT1 has the numbers 327 cast into the side of the block on both sides. Of course there are other numbers as well but I read that the "327" signifies the LT1. They are about 1" digits it says, again I've never checked. Look in the area between the 3 and 5th exhaust ports and anywhere from 2-4in from the bottom of the cylinder head. Can anyone else verify this info?

 

Yes the lt1 has 327 in the casting

 

Copied from Wiki:

L99 (4.3L)
A 263 in3 (4.3 L) was based on a 305 in3 with updated block architecture to be Generation II and a reduced 3 inches (76 mm) stroke. It was designated the L99, and was introduced in 1994 for the Chevrolet Caprice. It was externally identical to the LT1, but the bore was 3.736 inches (94.9 mm) and the stroke to 3 inches (76 mm) giving it a displacement of 263 in3. The pistons used in the L99 were the same as the ones used in the Vortec 5000, but 5.94 inches (151 mm) connecting rods were used to compensate for the shorter stroke. This was the standard engine used on all 1994-1996 Chevrolet Caprice Sedans. Including the Police Package vehicles.
Like the LT1, it features sequential fuel injection, reverse-flow cooling, and an optical ignition pickup. Output is 200 hp (150 kW) and 245 lb·ft (332 N·m). Due to its smaller displacement, it provides better fuel economy than the 5.7 L LT1, but at reduced horsepower & torque levels.

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It doesn't mention an external way to tell it apart from an LT1. I know that my LT1 definitely has "327" cast into both sides of the block. I have no idea if an L99 would have the same.

 

In the back of the motor at the top its stamped 5.7 I would assume the l99 wouldn't have that

 

ya its stamped

 

thanks, found it stamped above the flywheel.

the motor i bought has steel heads on it though. i already have a pair of aluminum heads but i've heard that steel heads flow better. is there any truth to that?

 

Flow better for low end torque. If you are going to upgrade the Cam to the Camaro cam or better then the aluminum heads are the way to go. If you are leaving LT1 bone stock changing the head by itself will not get you much except the weight reduction.

 

Wiki doesn't seem to be very accurate then. My 96 Impala SS made 220 horse and 270 tq stock.

 

Wiki is only as good at the folks who enter the data. They don't do a lot of checking unless someone can point out a mistake, and provide documentation to correct it.