I have a 26' formula 8' beam powered with a 350cu merc trs280 that has trani problems and I can't get parts. I'm thinking about a repower package. What would be the best combination? A merc 5.7l carb 250hp, volvopenn 5.7l carb 270hp, merc 5.0l fi270 or twin merc 3.0l carb 135hp, the cost is...