My engine, which I believe to be a 1956, has a casting number 567405. This is listed to be a 1956 block. My question involves the vent holes in flywheel area. Other blocks I've seen have screens in them. Mine are solid, no vents. Is there a difference between stick and Hydramatic blocks? All the ones I saw in the junk yard had vent holes. I'm going to run a Hydramatic. Don't believe there is any trany cooler. If this is a stick block with no vent holes, will this cause a problem when I use it for a Hydramtic. Are there any other differences?

Thanks,

DZ