See if this helps:
http://en.wikipedia.org/wiki/List_of_GM_engines

 

the LT1 was available from 92-97 in F (Camaro, Firebird), A (Caprice, Roadmaster, etc), and Y (Corvette) body cars. there was a slightly hopped up version of the LT1 called the LT4 available in 96 Corvettes that was the first (and last) small block to get 1.6 ratio Crane roller rockers installed at the factory. a similar 4.3 liter variant called L99 available in Caprices from 94-96.
think of it as the final evolution of the 265 OHV pushrod V8 that came out in the 55 Chevy with a bigger bore and stroke, one piece rear seal, cam driven water pump, reverse coolant flow, electronic fuel injection, center bolt valve covers, and a bunch of power right out of the box.
the GEN 3 engines (LS1, LS2, LS6, LS7, L92, LQ9 etc) are all part of the all new for 97 family of OHC V8 engines hat GM puts in everything with a V8 these days except for some Caddies that get the Northstar. they range in size from 4.8 liters (1/2 ton pickups) to 7.2 liters (ZO6 Corvette) in size, all in a compact and lightweight package.
the only things that it shares with the 55-98 small block is 90 degree bank angle, bore center measurement, bellhousing bolt pattern (but with metric bolts), and lifter bore diameter. everything else is all new and improved, except for the silly Ford style 4 bolt per cylinder head sealing scheme..

 

the LT1 was available from 92-97 in F (Camaro, Firebird), A (Caprice, Roadmaster, etc), and Y (Corvette) body cars.

Caprice and Roadmaster are B-body, not A... the LT1 was also available in the 94-96 D-body (Cadillac Fleetwood)

the GEN 3 engines (LS1, LS2, LS6, LS7, L92, LQ9 etc) are all part of the all new for 97 family of OHC V8 engines.

LSX engines are not OHC. They are cam-in-block pushrod engines just like the traditional Gen I and Gen II smallblocks were.

 

LS6 & LS7 are mark 4 big blocks...
I don't recognize them any other way:noway:

 

LT-1 Gen 1 SBC
LT1 Gen 2 SBC
LS6 Gen 3 346"
LS7 Gen 4 427"

http://www.ls1tech.com/forums/showthread.php?t=213148 has plenty of info on Gen 3 and 4 motors

LT1s and LT4s share the same crank rods pistons as a 86+ tradional SBC. The block heads and waterpump are close but have been changed for reverse flow cooling. Traditional SBC heads have been modified to work on LT1/LT4 but it is alot of work.

 

Correct me if I'm wrong but I think it's:

LT1: Basically a small block redone up with reverse cooling and the distributor is up front, center bolt valve cover heads, found in 92-97 Corvettes and 93-97 Camaros

LT4: same as LT1 but with a better induction/cam, I believe they came in Corvettes only but you can buy the parts over the counter

LS1: All aluminum block with 6 bolt mains and 15 degree heads, all in a world of it's own, found in 97 to ? Corvettes and 98-02 Camaros

LS6: Same as LS1 but with better induction/cam, found in Corvettes

LS7: 500 hp Corvette engine

LS2: 400 hp GTO engine

 

LT1 92-96 Corvette, 93-97 F body
LS1 97 to 04 Corvette 98-02 F body
04 GTO LS1
04 CTS-V LS6
05+ GTO, CTS-V LS2
05 to 07 Corvette LS2
08+ Corvette LS3

 

Where does the LS7 454 crate motor that was available until the early 90s fit in?

 

I think of it as a 454" L88. Higher compression and bigger cam than the LS-6 and aluminum heads.

 

LS6-V-LS6, LT1-V-LT1, Just GM's way of confusing the he!! out of people. Just like the 60's-70's NOVA-V-80's Nova, or the 60's-70's GTO-V-the 2000's GTO. The only link between them is the name.