Technical Rocket Oldsmobile V8 Information Compiled

My 57 has Milodon stainless small block valves with lash caps shimmed with hacksaw blades and Smith's adjustable pushrods. It still runs well after 20 years. The valves are 1.94 and 1.6 and mild big block Crane springs are used

 

Are those really 1955 rocker arms? How can I identify them?

https://www.ebay.com/itm/1955-OLDSM...ash=item2137efdca2:g:AksAAOSwL9paZP41&vxp=mtr

 

they look right to me.

 

And to me also but are you that desperate that you would consider those pieces?

 

Only thing to buy them for would be for the stands


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Thats one of my ideas. I scored a running 394 for my 55 Olds project and now I have two 303 blocks and a lot of parts laying around searching for a future for them. Here are more infos about the other blocks:
https://www.jalopyjournal.com/forum...ine-for-my-55-olds-rocket-88-project.1020134/
The block I bought later from Michael still has the original bore and was wearing #3 heads. Michael now wants to sell them and I'm thinking about getting all parts from that 303 back together to built a slightly modified 303 for a later hot rod project. But the heads will come without the whole rocker assembly since Michael put those in his own Olds. Maybe I can get his old 1:1.5 rockershafts etc. but one of the stands is cracked. Maybe the parts from ebay could help to get 1.8 rockers for this project, I was thinking. I will update the linked thread with pics of my new 394. Hmm, or should I start an own thread for the whole 55 project???
Anyway, I'm planning to rescue both 303 based engines I have if it's possible. First the 1953 303 and then the 1949 303 (it is bored to 324 already) with all the race parts it came with and i will add my weiand dual quad intake too.

 

I was at the shop today. I have to swap the engine of my girlfriends car but took the time to shot a few pics of the 394 and the 303. The 394 has #18 heads. So 1959 or 1960. Does someone know how much HP it is making? Behind the distributor there is only a 2. The 303 has a 321.




The 303 has a 321. Could that mean 21th week in 1953?

 

there should be a tab on the DS at the top of the block right below the head that sticks out a bit so you can see it with the head on. It will be in the middle of the block by the center exhaust ports. It should have a serial number on it which will ID the block. Might start with an A or maybe a V. Post it up when you find it.

 

What you are calling a 394 is a '59 or '60 371-240 hp out of a Dynamic 88, I see the stamped prefix "C"
If you clean off the back of the block where the numbers are you should see a large number 4, for a 4" bore.
394s have a 4 1/8 casting number.
the three digit date numbers will pinpoint the week and year of casting.
Your 303 was cast 32nd week of '51

 

Interesting! I bought the big one as a 394. That is a bit dissapointing but it will move the 55 nonetheless. I am at the Shop later. It is 20 Kilometers out of town. I will look for the other numbers then. The 303 had #3 heads and so we were thinking it must be a 1953 engine.

 

Frankass is that you?
So if you "only" have a 371 I wouldn't go crazy and spend much on it. Probably good idea to Check the bearings take the valve covers if, just some major inspections before you throw it into your 55 just to keep it running until you know what to do with the other
Engines and save up enaugh to build the "right one"
You know I could hook you up with some real 394 stuff, engine block, stroker crank and all...


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Hey double D, yeah it's me. Totally back into the rocket fever. You know I would call you begging to sell some of your stuff if I need it that bad
You know the plan. Take the probably running engine first just to turn the 55 into a roller and beside that working on the other engines and look what will turn out of them.
I took some more pics of the naked blocks and the 371 today. Not sure about the 3 digit number behind the dist. hole. When I showed the pics of the hopped up 303 to Tony, he said that the dist. clamp with two holes is 1949 and one year only. Look what 3 digit number the block shows:



Here are the cleaned section of the 303 with the #3 heads. Would really wondering me if they changed the heads on this one. If Paul is right it is a 1951 block with 1953 heads. Am I right?!



And here the cleaned section of the 371:



Is the "-4" for the 4 inch bore?

Random pic of our shop space


Here is the flexplate I need to bolt the Jetaway to the 371.


I will throw some more pics in my rocket related thread.

 

I for sure would say Tony has more knowledge about those engines than I'll ever have so I'd say he's right.
If your not sure if that 4 means 4" bore it would be easy to juste measure it out??
I don't have no flexplate like this. Those that I have which were used with 394 and SlimJim transmissions are more massive and look like a Flywheel and have a dampner plate attached to them. No torque converter you know...


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So the whole three digit date code thing just got thrown out the window.
that sucks.

as for the two bolt distributor hold down, yes for the 1949
but I have had at least one 1950 stamped block that had the two bolt holes.
must have been a carry over.

and yes the large number 4 is for a four inch bore on the 371

 

what is the stamped number at the deck surface on the 303?
1949 would start with 8A
1950 would start with A

 

Will check that next weekend. No chance to get to the shop before saturday.

 

Here's the casting numbers that the late Olds guru Don_Wow gave us:


1949--8A1001 TO 8A193864 H PREFIX=HYDRA MATIC
1950--8A194001 TO 8A568689 H PREFIX= HYDRA MATIC
1951--8C1001 TO 8C287312 B PREFIX= SYNCHROMESH
1952--8R1001 TO 8R214478
1953--R215001 TO R549482
1954--V1001 TO V355083
1955--V400001 TO V983275
1956--A001001 TO A385513

 

thanks man, the 8A verses A I posted above was from memory,
If DON_WOW said the above numbers are correct I would believe it.
(the numbers are stamped not cast)

 

So using the above list: my engine numbered 8C207278B is a 1951 303 synchromesh....
For us English this is for a manual gearbox (stick shift)?


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Yep

 

I found this on www.442.com today:


"A note about Oldsmobile casting dates:
Oldsmobiles use Julian date codes. All you will see is a number cast into the part from 1 to 365. It will look like a plate with the date was screwed into the mold for the manifolds. Unlike Chevy, which uses actual dates (like 3 C 69, for March 3, 1969), Olds will cast 62 for the 62nd say of the year. For originality and number matching authentication, make sure your julian date codes fall before your car was produced. Look on your block to the pasenger side of the distributor for you block date. Then make sure your manifolds were cast within a few weeks of the block."

If I got that right the 3 digit number is just the day of the year the casting was made. Sounds logical with my three blocks in mind. Maybe the only way to date the correct year is the stamped number on the deck.
Does someone know what that clock looking like thingy say? Maybe the hour the casting was made in?!

 

Can you use a Chevy thermostat housing on a olds 303-324. They look to be the same size.


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No

 

Are there any options. My radiator hose is right in the center. My housing kicks off to the side.


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Speaking about thermostats. What's recommend for a 303 and were can I get one. Thanks


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You could fab a simple adapter plate to rotate the stock housing or use another.

Here in the Northwest I use a 180 year round.

 

We use sbc thermostats in our 303 and 324.

 

I found the numbers on my 303 blocks last saturday.



So the R539878 is a 1953 block and it came with #3 heads.

Interesting is that the 8A526608H is a 1950 block and that is the one with the two bolt holes for the distributor clamp. As Paul mentioned earlier there are some blocks from 1950 with two holes.

 

I'll jump in here and ask a related question. Does your '50 engine (with the two distributor hold down bolt holes) have the plug in the oil line at the right rear of the block? I don't think the photo you posted has enough field of view to see it. I had thought my engine was a '49 for the last 10 years. but recently found it was a '51 (from the number stamped between #3 and #5 cylinders). Mine was mis-identified because of the presence of this plug. At the present time, I am of the opinion that the presence or absence of this plug is not significant in identifying these engines.

 

I'm not sure what kind of plug you mean, Tubman. Maybe you can spot it in this pic. There is this little bend close tubing on the right side of the bellhousing. Is this what you're asking for?