Submitted by: Kevan Morrison
Time for the semi-annual clarification on the "400" engine issue: The 402 engine was, in reality, the 396 BB with a .030 overbore. Chevrolet started the production of the overbore engine during mid-'69 production. The TRUE 400 engine was produced during 1970 (I'm not aware of any other years); it was considered a SBC (option code LF6). This is where it really gets confusing, complements of the Chevrolet marketing gurus during the late 60's - early '70's: If the 402 (option code LS3) was installed in a SS Camaro, Malibu, or Nova, it was known as a 396 (SS 396 apparently sounded better than SS 402). However, if, for example, it was installed in a non-Super Sport Malibu, then it was known as a 'Turbo-Jet 400", and was identified as such by a "400" emblem on the front fender. If the Malibu had a SBC 400, it was known as a "Turbo-Fire 400", with no external identification. Now - to apply the above confusing information to the first gen Monte's: For 1970, if you ordered the SBC "400" (option code LF6), you received a "265 hp Turbo-Fire 400 V-8 engine (regular fuel)". If you ordered the BB 402 (option code LS3, and known as a "396" in any Chevy SS except for the Montes), you received a "330 hp Turbo-Jet 400 V-8 engine". For 1971 and 1972, there was no SBC 400 (the "Turbo-Fire"), so the confusion was reduced somewhat. NOTE the difference in the engine names (Turbo-Fire vs. Turbo-Jet); this is where most folks really get confused, and with good reason! Took me quite a while to sort it out. Now - why is it very important to "call a spade a spade" (ie., a 402 a 402) here? 'Cause, you go wandering into a parts store, and tell the parts guy you want a water pump for a "400" (for example), and well, you may not get what you expected. There's quite a bit of difference between the two engines, and some of the parts jockeys definitely aren't real smart (found that out by experience!). Rob, that's why it's important to clarify to folks the difference, and to specifically identify the engine. I've never had any significant problems ordering parts for my 402 as long as I SAY it's a 402; I'd never identify it as a "400". If any of the folks here need additional info on sorting out the differences between the two "400" engines, there's several good books and magazines out there that can do it. The best I've seen is Motorbook's International "Chevrolet SS Muscle Car Red Book", and "Muscle Car Magazine". The Red Book, by far, does an outstanding job on explaining the differences.