HRM history of the SBC omitted the 400"?

[novadude]

Far as I know, no 4-bbl 400s in cars in the USA. Ever.

Starting in about 1973-1974, the full-size cars had Q-jets on the 400 ci engine (the 2-bbl went away). I have a 1976 400 out of a wagon that has definitely never been apart, and it came with the original Q-jet EGR Iron intake and Q-jet (with carb number that decoded to '1976 400 ci').

The 330 hp 400 mentioned above must have been Canada-only. The only 400 SBC available in US passenger cars in 1970 was the 265 hp 9:1 2bbl. The 330 hp '400' available in 1970 Malibus and Monte Carlos was actually a 402 BBC.

[F-BIRD'88]

The 2 bolt 400 block is the better choice for a perf build up.

The 4 bolt 400 block was famous for cracking right thru the main webs, just like mine did.

[F-BIRD'88]

Yup it was 1970 Caprice only. No mention of this motor in the Chevelle parts book.
The GMC Sprint (El Camino) came with a 2bbl 400SBC (265HP)
The Chevelles and ElCaminos came with a 402cid 396 BBC.
The Monte Carlos came with a 402 (396 BBC) or the 2 bbl 400 SBC.

The only mention of this 400 CID "330HP" small block motor was in the ImPala/Caprice 1970 parts book at the dealer counter.
I remember I looked this motor up in the parts book at he GM Dealer.
They used to give me the old GM parts books when new ones came out.

This 4.12" x 3.75" 330 HP 10.25:1 400 SBC motor is also shown listed in the my "Fix Your Chevrolet" text book.
The 9:1 "255HP" 400SBC is also listed , as is the 10.25:1 396 (402cid BBC) LS3
The 402BBC (396) LS3 is listed as 4.125" bore 3.76" stroke.
I had a few of these too.

[Jeff Lee]

My future mother-in-law had a ’72 Kingswood 9 passenger station wagon with a generic 400 2bbl & single exhaust. It was more impressive than most would think. Very torquey. I never knew they had that 330 HP performance package.

There were several 400 engines with a 4 barrel carburetor racing in NHRA "Super Stock" eliminator in GT cars.

GT SuperStock is another story. That is cars with engines that were usually not offered from the factory that way. You could build a 1996 Camaro with a 283 2bbl if you so desire.
NHRA does not list a 400 SBC 4bbl until 1974.

[SupStk]

My future mother-in-law had a ’72 Kingswood 9 passenger station wagon with a generic 400 2bbl & single exhaust. It was more impressive than most would think. Very torquey. I never knew they had that 330 HP performance package.

There were several 400 engines with a 4 barrel carburetor racing in NHRA "Super Stock" eliminator in GT cars.

Yeah, I was wondering about that too. A guy who Jeff and I know ran that combo in a Corvette (4barrel 400). Don't recall what year and HP for that engine though.

[pdq67]

Again, PLEASE!

"What would be the chamber size for a stock, 10.25 to 1 CR, flat-top piston 400" engine?

Say, with a, "DITH", of .025" and 6cc or so valve notches. Like an old L-48, 350SS engine was back then.

I have two 400's in my garage, one an early 4-bolt and the other, just a 2-bolt. Both have dished pistons.

pdq67"

pdq67

[SupStk]

Again, PLEASE!

"What would be the chamber size for a stock, 10.25 to 1 CR, flat-top piston 400" engine?

Say, with a, "DITH", of .025" and 6cc or so valve notches. Like an old L-48, 350SS engine was back then.

I have two 400's in my garage, one an early 4-bolt and the other, just a 2-bolt. Both have dished pistons.

pdq67"

pdq67

Geee I don't know since I've never seen a factory flattop 400. It was previously mentioned they were 441x heads so my guess like most of them, uncut should be around 76cc. Should have been easy enough for you to figure out if interested.

[DaveMcLain]

Again, PLEASE!

"What would be the chamber size for a stock, 10.25 to 1 CR, flat-top piston 400" engine?

Say, with a, "DITH", of .025" and 6cc or so valve notches. Like an old L-48, 350SS engine was back then.

I have two 400's in my garage, one an early 4-bolt and the other, just a 2-bolt. Both have dished pistons.

pdq67"

pdq67

Chamber size on all of those open chamber heads is normally between about 76 and 78cc. If you're down in the hole .025 with a 6cc notch, a .045 gasket with a 4.200 gasket diameter you're at about 9.4:1 compression. Now 4.200 and .045 for the gasket are probably somewhat out there for dimensions a little bit.

[F-BIRD'88]

The factory gm assembly line head gasket was not .040" thick. It was like .026" ish. It was drilled for the steam holes.
The replacement part gm gasket was not the same as the oem assembly line gasket was.
I took good note of this stuff on that 400 when i tore it down.


I did not Cc those heads thou .

[PackardV8]

Poor grade for reading comprehension and then getting upset by a wrong interpretation. The article was about the 350 version of the SBC and its history, nothing else. Why would a history of the 350 have to include the 400? It's not a complete SBC history, it is only about that particular displacement developed within the constraints of that early small engine block. Did you miss the years of production?

Yes, No, Maybe. For true the title of the HRM article is 350X50, but it's far from about "nothing else" or only the 350" years of production. Telling the 350" story, they give an overview of the SBC continuum, as well as various BBCs; detailing the 265", 283", 348", 409", 327", 396", 427", 302" and close with how it evolved into the varieties of the LS. No mention of the 400" seemed an unusual omission. But then, as you suggest, there's someone who'll bring up the omission of the 262", 267", 305", 307" et al.

[novadude]

But then, as you suggest, there's someone who'll bring up the omission of the 262", 267", 305", 307" et al.

We don't discuss 262 and 267 engines nearly enough around here!

Both of these in stock form really deserve to be forgotten. Especially the square 3.5" x 3.48" 267.

[psychomotors]

Far as I know, no 4-bbl 400s in cars in the USA. Ever.

Starting in about 1973-1974, the full-size cars had Q-jets on the 400 ci engine (the 2-bbl went away). I have a 1976 400 out of a wagon that has definitely never been apart, and it came with the original Q-jet EGR Iron intake and Q-jet (with carb number that decoded to '1976 400 ci').

The 330 hp 400 mentioned above must have been Canada-only. The only 400 SBC available in US passenger cars in 1970 was the 265 hp 9:1 2bbl. The 330 hp '400' available in 1970 Malibus and Monte Carlos was actually a 402 BBC.

I may be misunderstanding you but my 400 came from a 76 Monte Carlo - 2 bolt main , 2 bbl carb but I don't remember what heads but I'm thinking 882s or 993s because I used to have a bunch of those in my collection. This was 20 or so years ago but I still have the short block.

[novadude]

Far as I know, no 4-bbl 400s in cars in the USA. Ever.

Starting in about 1973-1974, the full-size cars had Q-jets on the 400 ci engine (the 2-bbl went away). I have a 1976 400 out of a wagon that has definitely never been apart, and it came with the original Q-jet EGR Iron intake and Q-jet (with carb number that decoded to '1976 400 ci').

The 330 hp 400 mentioned above must have been Canada-only. The only 400 SBC available in US passenger cars in 1970 was the 265 hp 9:1 2bbl. The 330 hp '400' available in 1970 Malibus and Monte Carlos was actually a 402 BBC.

I may be misunderstanding you but my 400 came from a 76 Monte Carlo - 2 bolt main , 2 bbl carb but I don't remember what heads but I'm thinking 882s or 993s because I used to have a bunch of those in my collection. This was 20 or so years ago but I still have the short block.

Maybe it was only full-size passenger cars that got the 4-bbl in 1976? My engine is out of a Caprice wagon. Factory Q-jet, 882 heads, single exhaust.

[rfoll]

I had a 72 Biscayne cop car with a 2 bbl 400. With a 3.08 rear gear it would run the 1/8 mile in 11 flat. Gm really missed the boat on that motor. Everyone goes on about the 70 1/2 Z28 350, but if you put the heads, intake/carb, and cam from the same motor on a flat top 400, tire life would have been a big problem.

[cv67]

Definitely....maybe GM knew if guys leaned on them they would break?

Had a perfect 400 2 bolt magged etc std bore. Just didnt want to sink a lot of $ in it and risk it breaking or doing something stupid like cracking when you torque the heads down that would be my luck lol.

Thing is couldnt give it away noone wanted it....or the 396 I had. Most go bigger or aftermarket these days