Overhead Cam? Anyways, FWD cars use a standard 200r4 or 700r4, but have a chain drive to the torque converter, so, you may be lucky and either of the two transmissions may still bolt up. The old FWD Caddies used a chain drivien transversely mounted th400 (which became the th475) on their 500 inch motor, so, I think the situation will be similar here.