[blykins]

A center oiler block isn't the best choice for a solid roller application because the lifter passages are not drilled. This forces you into a non-oiling lifter. Again, not a deal breaker, but certainly doesn't lend to longevity.

If you're looking for period-correctness, the BBM block looks pretty close, but it's not an original side oiler block. It's a new one. You get into the same deal as the "continuation CSX" cars.

I've used most of the aftermarket blocks. They are all nice.

I would urge against aluminum; I'm just not a fan. Yeah, they're lighter, but that's about the only pro in my opinion. You pay more for them, there's a lot more prep and babysitting during the machining process, and they take a little more "care" on the part of the customer.