If there is, does anybody know how to distinguish them from the 4.3??

Any help would be appreciated!

Charlie

 

I think the caprice lt1s had iron heads but correct me if im wrong

 

Yes. That's the L99, commonly called the "baby LT1" found in the Caprice. Externally they look identical to their LT1 brethren (aside from the aluminum heads - they had iron heads). Look at the intake manifold casting number. If it begins with "1010" it's an L99.

 

The engine in question here has 10125327 on the side skirt. Any idea?

 

That's a 5.7. If it has iron heads, it's out of the Impala.

 

Ok in doing some research here this is what I found out...

10168588...265...94-96...2...L99, Gen.II, 4.3 Liter V-8, Caprice, reverse flow cooling

10090511...350.....90....2...LT-5, ZR1 Vette, 375hp
10125327...350...92-up...2 or 4...Gen.II LT-1, reverse flow cooling
10125327...350...96-up...2 or 4...Gen.II LT-4, reverse flow cooling
10153558...350...91-92...4...LT-5, ZR1 Vette, 375hp
10199001...350...93-95...4...LT-5, ZR1 Vette, 405hp

Is the only difference between the first and second 10125327 the iron vs alluminum heads?

The reason I ask is this is potentially going in the 97TA, with my aftermarket heads...but I dont want to buy it if its a 4.3.

 

The "327" block was used in all LT1 and LT4 engines. The F-Bodys (Camaro and Firebird), and the Y-Body (Corvette) got aluminum heads, larger cam, higher compression ratio. The B-Bodys (Caprice/SS, Buick Roadmaster, Cadillac Fleetwood) got cast iron heads, smaller cam, lower compression ratio. The LT4 engine was used in the 96 M6 Corvettes, 29 97 Firehawks, and 106 97 Camaro SS's. Still aluminum heads, but higher compression ratio, very slightly bigger cam, and slightly higher compression ratio.

If the block say "327" on it its an LT1. However, when you open it up, if its out of a Corvette, it will have 4-bolt mains (or if it was a factory service replacement in an F-Body). The F-Body and B-Body blocks will have 2-bolt mains.

The 4.3L L99 is marked "4.3"

Read this:

http://www.lt1.org/lt1tech.html

 

The L99s used the same intakes as the LT1 and the LT1 was used with iron heads in more than just the Impala, it was standard in the wagons, Roadmasters and Fleetwoods. The L99 was the base engine in Caprice sedans only. Again BASE engine not only available the LT1 was put in grandpa's Caprice if he wanted it.

Easiest way to tell them apart is look behind the driver's side head, it will say 4.3 or 5.7 I'll let you guess which is which.

The L99 does have 327 on it in a few places so unless you know which location you are looking for 327 at it can be confusing.