Does anyone know the specs on 65 330 heads? Stock compression? Valve size? chamber size? How well do they flow when ported? I've ported a few Ford heads but never ported Olds heads. Is there anything I should be aware of? Thanks MIKE

 

This is a one year only casting with a 3/8ths-3/8ths stud.
Can be hard to find valve gear for.
I think it will have a 66-68 cc chamber with a 1.875 intake, and a 1.56 exhaust valve (both on a 45 deg angle).
Remember, these are not FORD heads, they have a 6 degree valve angle, and the port is aiming above the valve head (flow must turn more than 90 degrees to go from the port to the chamber. Ford specific porting may hurt these heads.
The ports are very similar until the late 70's heads when they started to go for mileage, and emissions. They can be ported to the 270 cfm range.
Jim

 

From what I have seen, the 65 "330" cid head has the 5/16 bolt and bridge rocker asy. The '65 425 head has the 3/8 rocker stud and half moon pivots and bridge asy.

Gene

 

As much as I hate to do this, I must differ from your statement, Gene.

The original heads from my 65 Cutlass had the 3/8ths stud arrangement.
Seen a number of original 1965 small block cars like this, unsure of their BDay. I would have to look up my 65's build date- not sure of that, either. I am sure of the studs, and rocker gear, and the heads being #2 castings.
My castings were cracked, as was the block, and I no longer have them in my possession.
With Gene's knowledge, I know he has had to have seen a #2 casting that was different from the norm.
Jim

 

mine are 3/8th's studs on my 65 #2 heads. bday jan 65

 

My #2 heads have 3/8 studs. When I ported my heads, I did it along with many other mods, so I can't comment on the before and after difference. I have been told that these heads, being built for high compression use, actually operate at pretty much optimal performance level straight from the factory. I ended up just rebuilding/replacing all the hardware and only ported the intake holes, to match as close as possible the the edelbrock intake manifold I was using. Definately don't do as u would with the ford heads...u may actually weaken their performance. Did I mention i burn posi straight thru 2nd??

 

By the way, my source on the head information was an old school oldsmobile guru who has a 67 cutlass 4speed with a 455ci, custom fabricated blower w/ dual carbs, pushing 725hp at the rear wheels!! U all should see this car...I'll try to take some pics next time I see him.

 

OH, i believe the stock compression is 10.25-1