IS THERE MUCH DIFFERENCE BETWEEN A 400 PONTIAC AND A 400 OLDS MOTOR ? Lew P.

 

Yes. absolutely everything is different. Absolutely nothing interchanges except maybe a bolt or two. The true meaning of apples and oranges.

John

 

Actually John, The Oldsmobile and Pontiac lifters would swap, and the starter would swap.

Unless of course the Olds 400 was '66-'67. Those had .921" lifters. and will not swap.

 

However, they ARE totally different motors.

 

Ah yep.. you are correct. But in the grand scheme of things? why?

John

 

Dunno....

BUT- Weren't the '65-67 Olds & Buick 400s the same block? What other similarities? I know back when I had my original 442, lots of people thought they were the same 'till I stomped on a couple GS 400s!!!!!

Ralph

 

Nope they were completely different castings.

The EARLY motors up until the mid to early 80's were factory specific motors. A buick is a buick, a chevy is a chevy Olds is Olds... and on down the line. it was only when GM started to put Chevy motors in other cars is when the "corperate engine" era began and a 3.4 was a 3.4 no matter what GM it was in.

John

 

Hmmmm.... I knew the GTO & SS396 were different, but never thought to check up on the Buick/Olds engines.
No wonder my Olds put a hurt on a GS 400! THX 4 the info!

Ralph

 

Until the mid-1970s, each GM division used their own unique engines. This is one of the things that differentiated an Olds from a Chevy, for example. Yes, there was some commonality prior to that, mainly in the lower-end cars. The Chevy I6 and Buick V6 are two notable examples.

Note that GM's slide in the marketplace pretty much corresponded to their decision to move to "corporate" engines in the mid-1970s. This also corresponded to cars that were pretty much simply "badge engineered" (different grilles and taillights only), which made consumers ask, "why pay for an Olds when the Chevy is the same car?"

 

[quote=German442;117201]Hmmmm.... I knew the GTO & SS396 were different, but never thought to check up on the Buick/Olds engines.[quote]

Buick motors use a front-mounted distributor, Olds uses a rear-mounted distributor. Completely different motors in terms of bore, stroke, castings, external dimensions, etc.

 

Parts that interchange: points, rotor, condenser, distributor cap.

MAYBE a few attachment bolts.

 

65 GS had a Nailhead 401 which stamped as a 400 ...

A Hot rodding relic of a motor that they replaced as soon as they could ...

 

i had a nailhead that was great i did a complete rebuild and drove it around for a year in a rusty 63 buick sold it to a guy that wanted it for a t bucket guess he liked the valve covers sitin flat on top of the heads but man that thing was a tourqe monster that made great hp on the mid range perfect for 1/8 mile.. imo one of the coolest buick engines

 

The nailhead was a great engine. They were tough and a really neat looking engine. The only problem as a performance engine was the size of the valves. I don't ever remember seeing any aftermarket aluminum heads which would have been cool. It came out in 1953 and lasted through through 1966.

 

Interesting history on the nailhead!

Again, no wonder I waxed them w/ the 442!

Ralph

 

Plus you could get the dual four barrel carb off a Riviera which helped out plus a switch pitch tranny ...

 

The Pontiac was further weird in that the driver's side bank was numbered 1,3,5,7 as with Olds, Chevy, etc. but the driver's side bank was behind, not in front of, the passenger bank. In other words, going along the crank from the front, the rods were 2,1,4,3,6,5,8,7 not 1,2,3,4,5,6,7,8 like Olds etc. Pontiac in the 60s also used cast "Armasteel" connecting rods, making performance enthusiasts back then look for 1958 or thereabouts connecting rods. Of course, the SD455 had excellent rods, but you had to have a car VIN to order them, as they were very limited production.