Technical Olds guys, what’s the difference between the 371 and the 394?

I may have a chance to pick up a 371 cheap. Not sure if it is a boat anchor or a good base for a hot rod power plant?

Performance parts interchange?

Shorter stroke?

Dog or gem?

 

I would like to know also. I picked up a gmc cab forward truck but don’t know the exact year of it because of no title. I has an Oldsmobile power plant.

 

I'm not an expert but I had a '63 394 Ultra High compression '88.
The bore is bigger on the 394.
The real thing about these Olds engines is they have 400+ ft/lbs
of torque usually maxing at under 2800 RPM as I remember, (STOCK)
Pulled that heavy '88 like a freight train.
Here's an old thread, but a lot of good info!

MOTOR, Early Olds Rocket tech summary.

 

I searched for the ultimate rocket thread but could not find it. That will have the answers to your question. If I remember right the 371 uses older style water pump and pullys ect. The 394 uses it's own water pump and accessory mounting brackets.

 

One thing is the 371 was available from 57-60, the 394 from 59-64, so there might be more 394s around. Don't seem to hear a lot about the 371, except as a J-2. Kind of like the 364 nailhead compared to the 401. Nothing wrong with it, it just got superseded by a bigger, more often available engine.

 

23

 

1/8 more bore

 

Here is some info
Technical - Rocket Oldsmobile V8 Information Compiled | The H.A.M.B. (jalopyjournal.com)
More
THE oldsmobile rocket 303 324 371 394 post to end all other posts, (lasalle related ) | Page 6 | The H.A.M.B. (jalopyjournal.com)

 

From my old TRW catalogue: The 371 has a 4" bore, the 394 is 4.125". Very few parts are listed as being the same. Same cam and timing chain, different rocker assemblies. There is a year change on the 371: 57-58 versus 59-60 also.

 

I believe this is true and important. I seem to remember that the late 371's have more in common with the 394's than with the early 371's.

Odd; when I think 371, I think "Olds Rocket"! When I think 394, I think "Late Model stuff".

 

57 58 371 was the final development of the original 1949 Olds V8. In 1959 they came out with a revised design in 371 and 394 cu in. The smaller engine for the Olds 88, the larger one for the Super 88 and 98. The earlier model has bolts in the middle of the valve covers, the newer one around the edges. Either is a good engine, heavy powerful and remarkably tough. Both could be taken out to 480 cu in.
There were some top fuel dragsters that used blown Olds engines, they would run with the Chrysler hemis.
Any 371 will make a good hot rod power plant. They were popular in their day and I would expect things like intake manifolds, cams, etc to be available.
Later... The last 371s were in 1959 - 60 Olds 88s. The 394 continued until 1964, for 1965 Olds got an entirely new engine, a 425 that grew into the 455. This was the same family as the 330 that debuted in 64 and later became the 350.

 

Not quite the Ultimate Answer, but damn close!

 

As already mentioned above, the 57-58 371 is a totally different design engine compared to the 59-60 371. (The cubic inch is the same because the bore and stroke are the same)

The later one has little to no value to most rodders for several good reasons. One is that there won't be much variety or availability of old speed parts like decent intake manifolds or even valve covers.

Next big drawback is that nearly all 59-up were A/T engines that need to have the crank drilled for a standard shift pilot bushing, and they also used an external balanced flywheel which would be nearly impossible to find. So you'd need to have the engine internally balanced to use an original pre-57 Olds neutral-balance standard shift flywheel or a $$ repro flywheel. You'd just spend far too much $ on those mods even before finding a vintage stick bellhousing to fit the trans you want, or a new repro bell which will also be $$.

Also , like Tubman hinted above, the 59-up Olds engines look more like a modern engine compared to the far more desirable early Olds Rockets.

Most (Olds powered) hotrods built in the 50s to very early 60s used 49-56 303/324 engines, and that is why there are so many different brands/varieties of vintage speed parts and valve covers still out there for those. That also explains why there are so few 59-up old speed parts to be found, as most old "street driven" rods rarely used the 59-up Olds engines....Chevy Sbc popularity was affecting the aftermarket demands by then as well.

 

So, it sounds like a polite "no thanks" is in order.

 

Dressed up 394 that was for sale here....Looks vintage except for the alternator...Not to say an earlier engine isn't better for the reasons mentioned above
https://www.jalopyjournal.com/forum/threads/63-olds-394-4-speed-dual-quad-sold.1011093/

 

You didn't say what year the engine is or what your end use would be.
But does sound like responders have made your decision for you.
Get an sbc, they will be happy with your (their) choice.

 

That was a '63, it came with an alternator from the factory.

 

You are a wuss if you don't buy it.

-Abone.

 

The most obvious difference was the deck height. The 57 and 58 371's had a different deck height from the 59-60 371's. Even though the 59-60 371's did not have the pilot bushing location, it was very simple to have one bored and installed. The flywheel/flexplate that would be needed on these engines are pretty simple to have counterbalanced.
As far as which 371 to use, I prefer the 59-60, since they are just a de-bored 394. Some of the 394 performance parts do fit in the later 371. The only performance part that is not available is the tri power (J2 option) for the 59-60 engines due to the different deck height.

 

Roothawg what do you consider cheap? I don't really want to know how much your paying just that I have a 394 complete but completely apart with a 4bbl carb and manifold plus some 371 stuff and I wanted $300.00 I still have it. I thought that was a cheap price. My brother Mike was going to use it for his comp coupe but sold the car.

Pat

 

Like $250

 

If you can use it that's a good price for a complete motor. If it's going to sit for a future project your better off adding $250. to your IRA? contribution.

Pat

 

It's not a Pontiac.

 

https://www.hotrod.com/articles/0901sr-oldmobile-v8-engines/
@GOATROPER02 from Ross Racing Engines would be able to answer your question

 

I had a 59 371 in a 53 Olds and it was a great engine,plenty of low end torque and plenty of top end and got decent gas mileage if I kept my foot out of it. Only modification was a 4 bbl off a 59 394 and it also ran good with the 2 bbl.

 

The 371ci Oldsmobile is a great engine for a Hot Rod. As far as parts interchange if you run heads off the 324ci you can run the early intake. We ran this one at Bonneville the last 2 years.


Sent from my iPhone using H.A.M.B.

 

Id buy it. But thats me. They dont grow on trees, and if you dont use it, you wont lose on it.

 

met a guy at the dover drag reunion racing a fed with either a 371 or 394(forgot). but it was running a hilborn on it. he said his engine guy told him he could run up to 8k rpm with no problems. WOOF!