Why were all the GM big blocks 455 cube?

[David]

Buick, Olds, Pontiac were all 455, Chev pretty close at 454. Coincidence?

[FMP]

There are no coincidences, it's a definite conspiracy outside of the previous 396-402,27, 400-425, 421etc etc and 472 -500Cadillacs

[SS Minnow]

Buick, Olds, Pontiac were all 455, Chev pretty close at 454. Coincidence?

Why they were all the same size? Economy of scale.

I have done some trim work lately. It is cheaper to buy base shoe that is pre primed, then it is to buy base shoe that is bare. Bare base shoe is ready to ship as it is. Pre primed involves a few more steps before it is ready to ship, so why is it cheaper?

[David]

It was not economy of scale, the engines were all different guts, bores, strokes, heads. As FMP notes, the big blocks evolved from different original displacements. All divisions made a 400 (396 or 402 for Chev) as GM had a 400 limit for mid size cars. But why 455?

[FMP]

Almost identical engine bay size, deck height bore stroke under over square between blocks differed slightly. 455 , has good appeal. Like the 396 to 402, still called it a 396. 454 sounds pretty good too and the bore stroke wasn't odd off the wall. Years before Buick had a nailhead that they called 465 or something, but was a 445 I think maybe I'm wrong it was a wildcat 465

[SS Minnow]

But it was just economy of scale. As time went by, there were less and less offerings. Not that people may not have wanted a certain power plant. Each individual GM manufacturer gravitated towards offering a smaller amount of power plants. Happened the same way with Ford, and Mopar as time went by. You wanted a small six, small block, or a big block. Look at the way it is now. It has all evolved as could be predicted. You want this, or that. No more options.

[FMP]

At Olds the baddest hp rear drive was the W33 Police Pursuit 455 in a 69/70 Delta 88 Custom or Royal not the W30 442 but the Hurst was nearly in tune, highest rated was the Toronado GT at 400HP. All had over 500- 510 torque rating. The Toro had the lowest hood clearance and needed a low intake but the exhaust side had some more room. The intake manifold from the 98, 88 Delta and Cutlass etc didn't clear under the Toro hood.
W33 Delta Police with the station's mechanic tune ran so good on the top end the deputies in the plane couldn't keep up to its ground speed during a hot pursuit of a couple armed bandits in a " getaway car" the big old had them.
True story

[RiverRat71]

I might be a little too young for you guys to get in this conversation but gonna anyway. I don't know what the diff was other than the fact that I know early 70's Buick GS 455 made more torque than any GM motor by far at the time. Look it up. My dream car is a Stage 4 GS. I had a friend that had a 4 door Olds with the same block that would outrun most anything from a kick with a car load of us. If it had a posi rear I think we could have taken it to the strip on Sat nights. RR

[FMP]

I've seen the write ups on the factory stage protos. Nice stuff. Yup 455 Buick had the high torque. Big caddy not included.
The Hemi Olds and big Olds cammers are another.
Had a 69D head non air full on 455 Delta. Car was not slow, lol. It was optioned to move. 455 red block .
Now have a 69 big C head 455 red block Delta air power power. I like the new blocks being made, lots of room for ci.
Before the 1/4 guys start on with wheel standing chev2 boxes, we get it.
Haven't seen a highway only 1/4 long.

Today's machines rule on reliable performance just lack in style a bit , had a 700+hp Shelby PU park next to me, shared a couple compliments back and forth. Night and day difference to the old junk lol.

[FUJIMO]

...the trans-am 455SD...what was that thing for h.p., etc.?...

[FMP]

Plenty lol
Net 335?
Big poncho angry
https://m.youtube.com/watch?v=OBxasFPEuDs

[David]

1973 SD was 310 SAE net

in the 70s and 80s GM started consolidating engines. One division would use another’s engines. Prior to that each division had their own engines

[Instigator]

GM got sued for cross breeding motors.

My dad had a 1980 Buick Lesabre w/a 301 Pontiac in it.
An absolute turd of a motor.
He sold it to me and I of course bolted a trailer hitch to it and blew it up.

[FMP]

The swapping of brands started in the 60s , the Chev l6 and small blocks found their way into some Pontiacs I'm sure of it.

301 2bbl ugg. Small block Olds was the last holdout Y and 9 code 307 4bbl. Not a bad engine at all, good wagon torque with a 2004speed w lockup OD. Last ones were rollers. 87 442 307 squeezed about 180 with a good flat torque curve, couldn't beat it to death if you tried. Somewhere around 89/90 was the end. Then only the Chev remained to date.
Still like the small block Olds 403, biggest bore of any small or big block Olds. Olds diesel small block 350 is a great start for stroker 426 or more with bb crank.