Replace the the heavy mohogany ply with aircraft grade birch ply using the old pieces as a template, MAC 67, CMB, ROSSI, OPS, OS, K&B,PICCO are the engines most used with the MAC and CMB being more of the race breed, the cost of a K&B is $450.00 when they come , you could probably find a good used engine of the race breeds for that kind of money. HYDROJUNKY has and is a regular pleathra of info on getting a dumas together properly.