[dwtaylorpdx]

I've had the opportunity to build quite a few race cars for road racing where we try and save weight. In the AL vs iron area we found Chevy Iron vs AL blocks had the 100 lb savings, but very very few others did. In some cases (Nissan 2.0 engines) the Iron version was 30 lbs lighter than the AL version. I've also seen a std 350 chev v8 block lightened up for a dirt track car by almost 100 lbs with very carefully designed CNC programs. They machined every surface making it thin as possible. Lots of the water jacket is filled with epoxy where the water is not realy needed to help stiffen up the block. Would not be surprised if any mid size 4 cylinder could not be lightened significantly.

Dave.