GM big blocks

[David]

The 400 limit for internediates was well known. But I don't remember a 455 limit. Another puzzler is tha all the divisions made 350s

[FMP]

As mentioned above the Hurst started the ball rolling,
https://www.hemmings.com/blog/articl...-hurst-olds-2/

We had a 69 Delta Custom hardtop 455 with the big valve D heads, it was a heck of a fast car. The HD THM400 was optioned, top end was amazing. Off light not too much would get around it for long, then up top it would eat the road. That engine in the intermediate was fun.
https://m.youtube.com/watch?v=NpmxaamNwhw

I'll add for the day before a Honda owner starts fart canning off.

What's puzzling, the 350 was the standard engine for lots of models. The 350 olds had a couple stages of power. The W 350 are very strong.

When you bought a Buick you received a Buick engine etc. Very few had cross branding division engines. That became more through the 70s them 80s.

[FMP]

When Chev brought out the first big blocks to replace the 409 etc, Cark K received one of the first hand full.

[rochelle howell]

Pontiac Trans Am worst offender for other brand engines. Late 70's, early eighties you could get Pontiac 400, olds 403, Chevy 305, or bastard Pontiac 301(turbo or non). 78 I believe was a olds 403 unless you got a 4 speed, then you got a Pontiac 400( last year for it)

[CDave]

Never knew there were different GM 455's. Thought they were all the same.

[FMP]

And 400s , 350s, 307s

[FMP]

Pontiac Trans Am worst offender for other brand engines. Late 70's, early eighties you could get Pontiac 400, olds 403, Chevy 305, or bastard Pontiac 301(turbo or non). 78 I believe was a olds 403 unless you got a 4 speed, then you got a Pontiac 400( last year for it)

And if you ordered the TA, bird with a trailer tow package you received the non web 403, as the 88 ,98 and wagons from Olds. Very rare block. 403 are big bore motors and are small blocks like the 350, 307, and the smallest 260, but have larger bores than the 455. If built with the right parts can be a great engine. As can the Diesel 350 Olds to gas.

[Forkin' Crazy]

Yea, a friend had a TA with a 403. With a little work it was very impressive at the drag strip for the money he had invested. I had a chance to buy it on the cheep (hail damage) and I regret not getting it!!!

[FMP]

Dick Miller build
https://www.hotrod.com/articles/0504...mobile-engine/

[rochelle howell]

And if you ordered the TA, bird with a trailer tow package you received the non web 403, as the 88 ,98 and wagons from Olds. Very rare block. 403 are big bore motors and are small blocks like the 350, 307, and the smallest 260, but have larger bores than the
455. If built with the right parts can be a great engine. As can the Diesel 350 Olds to gas.

Looked for a pic of non window 403. Seems like no one can come up with one?!?!?!?!

[FMP]

Not many around. I read it first in the 80s, it wasn't folklore.

[FMP]

Not many around. I read it first in the 80s, it wasn't folklore;

As far as 403's go, some people doubt that a solid web engine was ever made. According to Mondello, 2500 solid web 403's were produced in 1977 and they were used in big Buick and Olds wagons. You can determine if you have a solid web by looking at the serial number.
Quantity Produced 2500
Block Casting Numbers 557265-4A, 553990-4A, 554990-4A
Blocks with these casting numbers were used in certain 1977 Buick Station Wagons built in 1976, the Pontiac Bonneville with tow package, the 1979 Pontiac Trans Am with tow package (w/block casting #554990-4A), and in 1977 Olds 98's. Block casting number is found behind the timing cover between the oil fill tube and the oil sending unit. Might also be found in 1977 Toronados.
All "4A" blocks don't necessary have solid main webs. #554990 has been found to have open webs. 1977 models built early in the model year, fall of 1976, are likely to have solid main webs.
Source: Mondello Olds V-8 Engine Technical Reference Manual

[FMP]

Probably in the 3.23:1 HD wagons , also the Toro 403 front drive equipped GM motorhome of those years.
Motors made 330 torque at 2300

[XstreamVking]

The bad boy of the 455's might have been the HD 455 in the Trans-Ams. Way underrated by the factory, (285 haha) they were later given a 435hp estimate. They were a 73 and 74 option only. Lot of unique parts in them.

[FMP]

1971 Pontiac
L75-code 455 that touted 25 extra ponies, but there was still another available step to the LS5: a 455 H.O. (High Output) that gave drivers 335 hp and 480 lb-ft of torque to play with.

Then SD 455 , low compression in those years but still ran with the best of them.
The best 455 street from Buick stage 2 455, very strong. Would out gun a LS6 Chevelle.
The best from Olds was rated 400hp W34 Toro GT front drive. It was the same motor as the W33 Delta rated 390hp. The non AC car had a different grind than the AC, also I think the manual trans was more duration. But the 365hp version had the highest torque rating.

Then came the W43 four valve semi Hemi 455, absolutely beautiful. Then if that wasn't enough the OW43 Cammer 455 7000rpm 700 hp just the beginning.
https://www.streetmusclemag.com/news...hat-never-was/