The Stovebolt Site Forums The Shop Area Engine Shop What is a 322?

I was reading the post on engine colors in the paint and body shop...I noticed an engine called a 322.

I have never heard anyone mention it on here before.

What is a 322?

Just curious.

322ci. engines, were Buick engines, used in 1956, & 1957 Chevrolet Heavy Duty 7000-10000 series trucks. I've seen some reference of them also being used in some 1958, & 1959 Chevy 70-100 series Heavy Duty Trucks, but have personally only seen the Big Block 348 Chevy engines in '58, & '59 models.

Thanks Spanky...I figured they were kind of a rare creature.

I have never seen one, but have seen them in books on trucks. The nailhead 322 is a good engine, a powerful performer. They have soft crankshafts so if you run one long with a rod knocking it will chew up the crank. I had one in a 55 roadmaster that broke a piston and bent the crank, then it wouldn't keep the front crank pulley on.

For '58 and '59, the 322 was used primarily in the 10802 school bus chassis only.

OK, what can you tell us about a 366? A friend of mine told me today he had a Chevy 2-ton with 366 and claimed it's a Chevy engine.

A 366 is a variant of the tall deck big block Chevy. It was used in 1 1/2 ton and larger up to the early '90s. There was also a 427 built from the same block that was available until a couple of years ago in the Kodiac/Top kick models.

Cletis,
I know it's a big block truck engine from the 70's, but what years exactly, I don't know. I drove a mid 70's straight truck that had one, good performer,
Scott

I just sold a tall deck 366. It came out of a 87 GMC 7000 series truck. According to Mortec this engine was produced up to the early 90's. It came with a Spicer 4054D 5 speed tans. I still have the trans if anyone needs one.
Fred

The 366 replaced the 348 in medium duty Chevrolet trucks in 1966. Note the 348s were discontinued in Chevrolet passenger cars after 1961 but continued in the medium duty trucks through 1965

Those tall decks are low rpm engines. They use a heavy four ring piston and ussally a govener. Best thing you could do with one is use it for an ashtray. The deck being about 1/4 taller than the standard engine makes all the parts not fit anything else well. We used to take the blocks of the 427 models in and mill them off so we could put them in stock cars. Ended up it was cheaper to use a 454 block with the 427's guts in it.

I wouldn't necessarily call the tall deck block a strictly low rpm engine. The pro stock and pro mod guys have been using them for years to build the monster size (500+ cid) engines for their cars. As far as parts itercangeability, the main things that don't interchange are the intake manifold and the timing chain. Most everything else will swap, including heads, cams, and the crankshaft.

the 366 is a GMC engine, not a chevy, It outweighs a big block chevy, and usually has a cast steel crank

I delivered lumber with a '69 366 when I was 19. We used to overload that thing mercilessly, and you'd better believe I got every ounce out of that truck. She was a tough old girl, for sure!

That's not actually correct. It is a Chevy engine, a variant of the MK4 big block to be exact. GMC didn't start using them until the late '60s when they went to using Chevrolet engines in their trucks, and even then they used their 60 degree V6 and V8s up to the early '70s. As to the increased weight, that is due to the taller deck hight ans wider intake manifold. Also, I have seen them with both cast and forged cranks.

There are spacers available to use a standard passenger car manifold with the tall deck 366 and 427 truck blocks.
LB I believe the timing chain is the same however the distributor is longer in the truck block but there are also manifolds that use the passenger dizzy with the truck block. As LB stated that t truck blocks are popular with guys who build large stroker engines.
Bill I don't know what blocks you were using but if you decked a standard 366 or 427 block a 1/4" you would be in the cooling passages or be so thin you would have a useless block but when building a big block with a stroke over 4.25" the tall deck block will allow you to use long rods decreasing piston skirt loading and increasing piston dwell time at TDC.

I have a 1957 Motor's Truck Repair Manual.
Under the Truck Models & Engine Application section the
322 is listed for '56 and '57 model 9100.
The 322 is listed for '56 only on models 9200 thru 10700.

Their was a 322 buick nailhead engine, I had one in a 55 Roadmaster Hardtop once....had a Dynaflow trans. GMC used Pontiac V8s back in the 50s. Maybe Pontiac had a 322 also, I would be a different engine probably.....Although I remember Olds or Pontiac used Dynaflow transmissions for a while when the Hydramatic plant burned one year. Maybe something liked that happened.

The 322 was used as an option engine for the heavier Chevy trucks from '56-'59, mostly in tandems. After the 348 came out in '58, it was relagated to school bus use.
Funny, I just answered the same question on a model car site-they needed educated on Task Force and Blue Chip engine options.