Doug Redinger
Seaman
- Joined
- May 22, 2005
- Messages
- 73
I have an old 1960 merc 300 (35 h.p.) that I rebuilt a few years back, and it runs really well for a motor almost 50 years old. I was thinking of kicking up the horsepower a little if I could. My question for the old time merc guys is this, will a front 1/2 of a crankcase from a merc 400,450,or 500 of that era fit the back half of a 300 crankcase. The 300 crankcase is 40 cubic inches will the others are 44 cubic inches. I already have the larger carbs on it now from a merc 400( had to modify the mounting flange on the carbs to get the larger carbs to fit.) I believe the reed valves are the same although I am not completely sure. Did the merc 400,450,or 500 come with a tuned exhaust baffle. I know the 300 just came with a flat stainless steel plate for the exhaust. If so will a tuned exhaust baffle from the higher H.P. models still fit the smaller 300 block.
Will a 400,450,or 500 powerhead of that era fit onto the 300 midsection without any problems. I am sure I can use my starter, ignition and so on from the 300 on the larger powerheads.
Will a 400,450,or 500 powerhead of that era fit onto the 300 midsection without any problems. I am sure I can use my starter, ignition and so on from the 300 on the larger powerheads.
