56 Catfish

I picked up a 1956 324 engine without the vent holes yesterday. I'm new to Olds and didn't realize there were 2. The guy I bought it from mentioned it not having vent screens but it was out of an automatic. I thought that was a little weird that he mentioned screens but not really knowing better, i bought it. The one in the car is vented (which I really never paid attention to).. From what I have quickly found, one is for automatic transmission and one is for manual transmission. Is this correct? Can the non-vented one be used with an automatic?

Charlie Jones

In my 1960 Oldsmobile Chassis Parts book it does list two different blocks.
Part # 567593 was used with 1956 standard trans and type "O" Hydramantic, (dual coupling type )
Part # 568547 was used with 1956 type "R" Hydramatic ("slant pan" single coupling type)
The Hollander I have mirrors this info and makes no mention of interchangeability.

I do know that the crankshafts were different. In that those used with the "slant pan" type "R" were drilled for a pilot bushing.

56 Catfish

I do have the hydramatic transmission. How do I know if it is the type "O" or "R"? The pan is not slanted under the car. I will research it a little more when I get home from work. Thanks for the info!

Charlie Jones

The dual coupling type "O" trans has a "park" position.
The "slant pan" type "R" trans does not.

56 Catfish

awesome! I do have the park so it may actually work! Now the question is "will it get too hot without the vent holes?" LOL

Charlie Jones

I don't know about the vent holes, but, the type "O" trans engines had a different crankshaft than the "R" types.
The crankshaft flange is different, Type "R" has a pilot bearing. "O" type doesn't.
It may fit anyway, but check it out carefully.