".....He is building a 30s model international rat rod, and got a good deal on the ol HEMI....."

Not trying to be a smart a$$ but the reason the extended bellhousing 331 are cheap is because of the transmission issues and they have the least deseriable smalll valve/small port heads. They also cost as much as the better HEMIs to rebuild.

".....was wondering if anyone has ever milled off the rear portion of the block, and made an adapter plate say out of 1/2" material, and mated a standard mopar small block bell housing to it?......"


On another site I frequent there was a guy who did this....he was a machinest by trade. As I recall there was a ton of hours involved making pretty impractical $ wise if you needed to farm the work out.

Personally would just dig up a GM transmission spend the $400 for the adaptor and try to find an original flywheel if he doesn't already have ove....it will be cheaper in the long run.