Can anyone tell me what cfm is on the stock carburetor on a 87 Mercruiser 260hp and if possible tell me if I need to increase that by rebuilding the engine, boring the cyclinders out .030 and adding high performance sporster heads with 202 valves?
the stock carb on 350 cid engines is 650 cfm if it's a 4 barrel. If it's a 2 barrel, then I'm not sure. If you have a 4-barrel (Holley?) then at worst you should only need to re-jet the carb since it has fixed jets. If it's a rochester or other with adjustable jets then I think you just have to set up the carb right.<br /><br />If you have a 2-barrel, definitely go buy a 4-barrel.
