I ran into this same issue when putting the toploader in my car. I had both bellhousings available. Just picking each one up made me go with aluminum. The cast one is damn heavy! The aluminum one looked pretty tough to me too. Other than clutch failure (which only a scattershield can really help) I've never seen a aluminum bell housing fail in a street driven car. I say go for aluminum.
http://216.71.48.244/archive/mikecar.jpg
65 Fastback 289 4spd in storage :-(
91 CRX Si... A.K.A. my go-kart with AC!
http://216.71.48.244/archive/mikecar.jpg
65 Fastback 289 4spd in storage :-(
91 CRX Si... A.K.A. my go-kart with AC!