New to the board with a few questions

Have a 1990 V20 with Alpha One/Engine 4 cyl 3.7 165 Mercruiser.
Questions:
- Trying to find out what the best replacement prop. would be, and what the pitch would need to be.
- Also, in need of a replacement power trim gauge that fits into the dash.
- Best place to purchase replacement parts for this V20 beside Ebay, and Craigs list?


Thanks to all