just got a 1973 tri sonic with in line four, needs new raw water pump have no idea which drive it is the # is 3506268, any help would be greatly appreciated
You have a Mercruiser '1' drive (known as an 'MC-1', or just '#1').... Some stupid people who haven't a clue what they are talking about will tell you it's a 'pre-alpha'. The answer is yes, it's before the Alpha One drive, but 15 other drives also fit that description.
To find the right parts, you'll also need to know if you have an external flushing attachment hole in the gear housing. Once you know that, look here for parts you need -> Mercruiser Water Pump Repair Kits - iboats
