Hey All,

A noob question...

What are LT1s, LS1s, and their variants and what do these terms all mean?

Thanks

 

LT1- 350 CID generation 2 small block Chevrolet. Used in 92-96 corvette and 93-97 Camaro/firebird. Also used in impala/caprice for a few years. Other variants are the 4.3 liter v8 version of the "LT1" used in the caprice/Impala platform, and "LT4" used in some corvettes. LT1 is by far the most common generation2 small block, the 4.3 v8, and LT4 are based off the lt1 with very few differences internally, almost all parts interchange between the three.

LS1- first generation3 Chevrolet engine beginning in 97 with the corvette, and 98 with the Fbody. Basic architecture of blocks and cylinder heads, ect., are shared between the LS2, LS6, LM7, LQ4, LQ9, ect.. These engines are also the "same" as far as physical external dimensions, and mainly vary in bore, stroke, cams, and such. Hence the later engines based off the ls1 are "variants"(of the original design).

When doing engine swaps, swapping in a lt1 or lt4 would require the exact same procedures. swapping in a ls1, ls6, or even a 5.3-6.0 truck engine(once fitted with car oil pan, acessory drive, and manifolds for fitment), require the same modifications to work in our car. All these parts interchange between the4.8 5.3-6.0 truck engines and the ls1, because they are of the same family or variant of engine .

 

If you are debating which to buy/swap. Just go LS. I loved my 355 and 383LT1's that were in my Old Iroc-Z But once I went LS it opened up so many options for aftermarket. LT1 is very limited as it was only a 4-5 year run. The reverse cooled heads killed the aftermarket for heads.

LS just has so many more options.

Jay

 

Something I hate about GM is their reuse of designations. A 2008 Impala is nothing like a 1965 Impala, for instance.

Similarly the LT1. In 1970, it was "LT-1", a Gen I SBC with a little better heads and cam than the run-of-the-mill 300 horse 350. It had a solid cam and terrible street manners. The highest rated Gen I SBC used in a production car.

Then in 1992, they brought it out again, as "LT1" this time, as the top line Corvette engine. Of course, it also went in f-bodies the next year. EFI, reverse-flow cooling, improved heads and chambers, it was the new highest rated SBC (since 300 net FWHP > 370 gross FWHP) with great street manners.

Now, they're using it again in 2014 - the next generation "LS"-type engine will be called "LT1". 6.2l, direct injection, "active fuel management", 450HP/torque, sounds like a great engine. But, why, oh why, did they call it "LT1"???

 

Thanks for all the great info.