Hello,
Could you tell me what 330ci I got and how can I do to know exactly its year of production ?
The code found on the front of the right hand cylinder head is T606607.
T for the year, either 1964 or 1965 but I didn't find exactly if it's 64 or 65 because I don't know if it's a 230hp (8.75:1) or a 250hp (9:1)
Thanks for your help !

 

If it has a large #1 cast by the #1 and #8 spark plugs its a 1964. If #2 then 1965, #3 is 1966 and #4 is 1967. That's the easiest way to tell as long as the heads are original to the engine.

 

Here is an old thread with photos of what I'm describing.
​​​​​​https://classicoldsmobile.com/forums...hipping-90568/

 

Olds started using the #2 heads very late in the 1964 model year.

Intake casting numbers will also help identify the model year.

 

Could you give me some more precisions about where may I look on the intake manifold ?
And where I can find informations when I got these casting numbers ?

 

Do you know what months of the end of 1964 are concerned by the application of the #2 ?

 

The casting number on 330 intakes is usually located on the runner behind the carb. Post a photo.

 

 

Thanks a lot Joe, but, when I know this number, where can I find correspondences with the year ?

 

I have a list. Again, post a photo of the number.

 

Model year '64 would have the lower radiator hose on the left side of the car. '65 on up would be on the right side.

 

Mine is on the right, so, '65 on !

 

Here is my intake manifold and its number !

 

And the big "2" on the cylinder heads !

 

Both heads and intake are 1965. Your #2 heads have the unique 3/8" rocker studs and matching rocker pivots. Those are one-year-only.

 

Thanks a lot, guys !

 

That is a two barrel intake. Could that be high compression or low compression, or low compression only?

 

That is the question !

 

The only 330 2bbl motor offered in the 1965 A-body Oldsmobiles was the RPO L65 motor with 250 HP and 9.0:1 CR. The Jetstar 88 that year came standard with a 10.25:1 CR 2bbl version of the 330 that was rated at 260HP. The L65 was optional in the J88.

 

Thanks Joe, Did compression ratios or horsepower ratings vary for export?

 

Good question. I'm showing 9.0:1 as the lowest CR for domestic production, but I'll have to dig up the export numbers.