Settle an argument for me guys

[toolboxchev]

Dam, I was hoping to see some black eyes and broken noses! Ha!

[Already Gone]

The answer is no and this thread made me smile as it came close to being like a lot of Facebook posts only without the insults and bashing.. Although as we speak I've been gathering parts for a SBC 400 build to replace my still running great original unmolested 90,000 mile 350 in my 72 C10.

[Accelo]

Originally Posted by StingRay

No is the correct answer. 402 badged as a 400 but 402 cu in.

You are correct. GM spend $ on the marketing and didn't want everyone to think it was and different. The emissions requirements changed that year. The amount of pollutants was split into two categories. Under 400 CI and over 400 CI. By increasing the displacement the BBC fell into the over category and didn't require major reworking to meet the requirement. That's the reason for the displacement change.

[Cake]

Attached is from a sales brochure from 1970. 400 is listed

[Cake]

Here’s the attachment

[mr.mud1]

Originally Posted by Cake

Here’s the attachment

yes sir,you are correct,a 400 is listed but it's not a small block 400,it's a 402 big block that Chevrolet called a 400.i think you'll see a 307 small block v-8 and a 350 small block v-8.that's it for the small block in a 72 truck.

[71CHEVYSHORTBED402]

What's interesting to me is why they threw a 400 badge & SPID description on a 402. I've heard they desired a 400, but wanted more CI to distinguish it from a small block because it's a big block. Something like that. I can't remember how the owner's manual reads, but the emissions sticker on the fender reads 402.

Lots of people believe these have a 400 small block. It's GM's fault

[Killer Bee]

I'll summon Keith again if he's available or someone else with the factory knowledge to clarify, but I believe the 402cid bbc was the result of something that occured with the 396cid bbc of that era..

[chevmn]

The 402 is simply a .030 overbore of the 396 beginning in 1970. To add to the confusion, many 1970 models such as the Chevelles were badged 396, but most if not all 1970 model "396" were in fact 402's, and built until 1972 when they dropped the 402. I used to have a 72 SS Chevelle with the same 402 as my C20 has (both were factory engines). In 71 and 72, they had dropped fender badging except for the 454. If memory serves, from 68-70 all "SS" Chevelles were big blocks, then in 71 they resumed small block production in SS Chevelles. Some literature states that GM wanted to keep advertised cubic inch to 400 or below until 1970 in many of their vehicles, thus all those were pretty much advertised and badged either 396, or 400, but as others mentioned, the emission decals accurately showed up as 402.