ok before you start to slap me for this comment hear me out. went to a car show this weekend out here in Cali. guy has a 400 in his s10 and its a damn nice truck. i asked him what year block and he tells me its a 99. and proceeds to tell me about the "not mainstream" vortec 6.6L that was offered in GM trucks. but yet i can find no info on this engine anywhere. i think this guy is messing with me but any input would be awesome.

 

haha that wasnt an option in any way.
Its prolly a 6.0L and he thought it was a Duramax 6.6L

 

even GM said they never produced a 6.6l after the 70's but im know there are people on here that know way more about GM than any human should so im hoping someone chimes in.

 

never heard of a 6.6 vortec,6.2's but not a 6.6.

 

im pretty sure the only years they made the 4 bolt 400 was 1970-72. i think he pulled this engine from a 99 truck but it was not the original engine. unless its a dart block or some other aftermarket company

 

While there was never a factory made Vortec 6.6L, one can be easily made using a standard bore 6.0L block and a 4.00" stroker rotating assembly (402 CID = 6.6L).

 

There was one advertised on craigslist around here a few weeks back. Guy said it was a 6.0 vortec 400 and wanted 1200. I think he was confused, just as in your case.

 

That's some funny stuff.

 

Weren't they offered in Mexico? It's not an LS motor but an old sbc instead. Seems like there used to be a white truck on here that had 400ss on the side that everyone made fun of but it was actually legit

 

LOL the '' Mexican " 400SS in 1999 had a SBC 350, 2000 to 2005 they just came with a 5.3L never got a bigger engine then that, I tried buying one and found this out kinda gay but oh well, but to this days people who drive or own them will claim to have a 400 in it but no just a 5.3L, run a vin# on one itll tell u