Chevelle board? A question on the 396/402

does anyone know of a good Chevelle board? A buddy and I are looking for an answer to this question:

In the current Hemming's muscle machines in the 69 Chevelle SS profile it states the 396 was increased in size to 402 later in the 69 model year. meaning that some 69s got the 402. My buddy swears it was a year later meaning that all 69s got 396s and 70 was the year that had both.

Sorry for the non-mopar post.

Thx

https://www.chevelles.com/forums/155-2006/149183-402-vs-396-a.html A 402 is a .030 over 396 some late 69's got them. Mike

All Ive ever heard was 1970 is / was the 1st year it was actually a 402 but still badged as a 396

Team Chevelle would be the place - I'm on there now that I have 67 SS. Some very knowledgeable people on board - like here.

Seriously, no one can tell the difference in 6 cubic inches.

When I was a kid we used to think that the 396 was the hot setup and that the 402 was a dog. Not sure why, that was just the "word on the street" back then. But really if they both were built with the same parts then they should run just the same. The L98 402 was pretty stout with 375 hp rating. I'm not sure on the '69 and '70 thing. Officially the SS 396 was actually a 402 in 1970 but it wouldn't surprise me at all to find out that some of the '69 cars got 402 engines. The factory wouldn't care that much about that stuff. They just put them together with the parts they have on hand.

I don’t think that is the point. And a micrometer certainly can.

The 402 kinda got overshadowed by the 454.

the 402 is to the 396 (Hollander lists the change as late '69 model year)
as
the 400 is to the 383

designed with bigger bores to clean up the engine's emissions - the majority were mid '70 builds in the low compression/smog/non-performance era and their reputation suffers

I kinda disagree with this, but only for this reason:

All engines experienced a natural progression of cubic inches. The BBC started with 396 and went to 427 and 454. The 402 in between that sequence may or may not have been for some emissions reason, but notice the increase was marginal.

Compare it to the B engine, which went from 350 to 361 and 383 and 400. Notice the last leap was 17 cid, which was not insignificant.

This site (http://www.chevellestuff.net/1970/70ss.htm) suggests engines under/over 400cid had different emissions regulations, and tweaking the 396 to tip over 400 may have solved the issue. But what was the issue?

Regarding the OP's query, I don't have the article in question, but let me offer an opinion that Hemmings is wrong when talking about Chevelles and partially correct when talking about the Camaro. For most of the Chevys, the model year began in Sept, but the Camaro was delayed into the beginning of 1970. Hence, 1969 Camaro production was extended into November or December 1969. I would think these cars built in August through the end of the year came with 402s.

Wanna hear something confusing? The 402, as optioned in Chevelles that were not SSs, was called the 400. So there was a 402 that was marketed as a 396 AND a 400 (and, no, not to be confused with the 400 SBC)!

here is the section from the article.

C10 pickups were the same way. A Cheyenne badged as a 400 would have a 402 in it.

Kevin

Yeah I remember running into the 400 emblem and assuming it was a small block but it was a big block. That 402 had a real identity crisis. I think the marketing folks knew that the 402 was considered a dog so they didn't want to tell anyone about it. Weird stuff.

I've heard the 402 is a bored over 396 block due to casting issues with the blocks. It was just a way to salvage a bunch of parts and labor basically.

have you ever seen a 396 with a smog pump, how about a 402? additional components cost $$$ (the minimal increase in displacement was a cost consideration, a new block was not engineered)

in the mid-'70s 440s received smog pumps in CA (low production quantities) but was not required on the 400 (larger production numbers offset the costs bringing the new engine to production)

& to save costs, Chrysler Corp. wanted the new "B" engine to share its bore with the 440 at 4.320", but with the 3.375 "B" engine stroke that would've been 396 cu.in. (wasn't going to happen )

someone suggested "400 cu.in." sounded better & bore was increased to 4.342"

The 70 SS had 396 or 454 badges. The 396 was a 402 even thou it said 396 on the car. The 402 just like the 396 came in several HP ranges some good heads some not. Some dogs some not. It was done to meet clean air standards. The engines had to pass a new and 5 year test. The 427 couldn't pass the new test for passenger cars and was gone. The 454 could pass the new test but not the 5 year test and that is why the 454 SS trucks came out to get rid of the 454 engines because the trucks didn't have to meet the clean air standard.

Although I am a diehard Mopar guy, I have always liked Chevelles .. this is my friends 70 a former Super/Stock car now a street car. He bought it from his good friend who was the original owner.. car is gorgeous!

The only one considering it a dog is you.

In 1970, the top 402 had solid lifters and 375 horses. This engine, known as the L78, is pretty famous.

The 402/330 that was introduced for regular Chevelles and the Monte Carlo is known as the LS3. It continued on for a few more years. being rated at 300 horses in 1971 and I can't remember what in 1972. How does that compare with dog 383s and 400s from 1971 and beyond?

Like I suggested, it's just your perception.

If the marketing guys thought the 402 was something special then they would not have called the car the SS 396. People back then thought the 402 was a dog even though it was basically the same as the 396. Just got a bad rap, same as the 400.

Wanna hear something confusing? The 402, as optioned in Chevelles that were not SSs, was called the 400. So there was a 402 that was marketed as a 396 AND a 400 (and, no, not to be confused with the 400 SBC)!

I bought a 71 Impala for the drivetrain and it had 400 badges. I never opened the hood until I got it home. I bought it dirt cheap. When I opened the hood I realized it was a big block 402. What a nice surprise as I installed it in a 71 Malibu. It wasn't a race horse but it would lite the tires up at 30 mph when you mashed the pedal.

Yeah the Chevy marketing guys really didn't want to tell anyone it was a 402 for some reason. They pitched it as the 396 or the 400 even though it wasn't either. I understand the 396 thing since it was basically the same engine and was a carryover but the 400 badge was confusing since they had a SB 400. They must have thought it was a good idea at the time but 50 years later it is confusing and odd. Nice score on the 402 big block though, funny that you didn't open the hood until you were home. Had you been counting on a SB 400 you would've been confused for sure.

Actually, it’s quite the opposite—there was tremendous brand equity with the SS396 name. Why ruin it?

You’re still failing to realize the 402’s heyday is the low-compression era, even though it was introduced in 1970. Its reputation is no different than a 400 B engine, 400 Pontiac, or any other mid-level engine from the era.

The insurance industry was also clamping down on big displacements, keeping under the 400 level by maintaining 396 badging was considered wise by some at GM.

The marketing guys didn’t call it a 402 because: 1. The 396 was an already established engine. 2. SS 396 sounds better than SS 402.

Maybe, but why did they also call it a 400 rather than a 402? It seems pretty clear that they didn't like the 402 name since they didn't use it. I don't know why they didn't like it but it is obvious that they didn't want to advertise it. Kind of reminds me of when GM put the Olds 403 in the Trans Am. They didn't call it by its name either at first. GM ending up paying something like $40M to settle a lawsuit over that.

Seems Pontiac did call the 403 for what it was after all:

http://www.lov2xlr8.no/brochures/pontiac/77pti/bilder/9.jpg

Lots of perception/reality here.

I thought the Firebirds with the Pontiac motors had 400 on the shakers and the 403 had 6.6?

I think the auto cars got the 6.6 liter sticker and 4 speeds got TA 6.6 (400/220 hp)? I can't recall for sure anymore, and I may be mixing up years here, at the dealer the "official" way was to look at the VIN, if there was a K (I don't recall the 400 code anymore) in it, it was a 403, it not a 400. What we really did was open the hood.

The 403 was a tire smoking torque monster, pretty well out of breath by 20 MPH. The base 400 was stronger overall even if the bottom end was a bit softer. The 220 hp 400 was impressive for the time. The later turbo cars were soft on the bottom end but after they came up on boost they ran strong.

Anyway, FWIW, best I can recall 40+ years later.

edit: a memory returned, I'm only talking about 1977 and later. 1977 was the first year for 403 in a Pontiac. And Buick 350's in the big cars...

T/A SHAKER stickers originally:
6.6 LITRE = 403 Oldsmobile
T/A 6.6 = 400 Pontiac

I think the T/A was only on the 220 hp 400, not the standard version. I can't recall the standard 400 HP but it was better than the 403 / 180 hp. Does W72 sound familiar, that might have been the 220 hp engine? I remember WS6 was a handling option? Included 4 wheel disc brakes?

I know if it was as easy as the sticker they wouldn't have had us checking VINS for codes. 2¢

stickers can be easily changed/removed - yes a dealership would have you confirm the original engine installation by the VIN
Oldsmobile 403 (VIN code "K - 6.6 LITRE") was 1977-79 ONLY & the ONLY Pontiac 400 available 1977-'79 (VIN code "Z" - T/A 6.6")



1977-'78
L78 Pontiac 400 - automatic ONLY
L80 Oldsmobile 403 - automatic ONLY
W72 Pontiac 400 - automatic & 4-speed (W72 "Performance Package")

1979
L80 Oldsmobile 403 - automatic ONLY
W72 Pontiac 400 - 4-speed ONLY (W72 "Performance Package")

Did a bunch of work on this 72 C20 a couple years ago. Has 400 badges and has it's original 402 in there.