Thread: Rect. vs. Oval

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well your heads you have are alum and the 049 iron heads are heavy . the 375 hp mercruiser did run rect ports . why not just take your alum heads and cut them to get the cr up . your 049 are not in stock form going to run better then the rect ports at 5000 rpm i really do not think so very low rpm maybe like off idle but i work on many boats never seen to many just idle what is the casting number on the alum gm head that are 124CC??? you have a 19 foot v drive you would be nuts to run them heavy boat anchor 049 heads if you want this thing to move you have to run it were it makes power the boat is not heavy?? 19 feet of boat? run the rects heads cam it to make power run the right prop

Originally Posted by pat mccarthy

well your heads you have are alum and the 049 iron heads are heavy . the 375 hp mercruiser did run rect ports . why not just take your alum heads and cut them to get the cr up . your 049 are not in stock form going to run better then the rect ports at 5000 rpm i really do not think so very low rpm maybe like off idle but i work on many boats never seen to many just idle what is the casting number on the alum gm head that are 124CC??? you have a 19 foot v drive you would be nuts to run them heavy boat anchor 049 heads if you want this thing to move you have to run it were it makes power the boat is not heavy?? 19 feet of boat? run the rects heads cam it to make power run the right prop

The casting numbers on the aluminum heads are #3946074. They are advertised as a 114.8 cc chamber but have been worked extensively, as have the runners. The cam is a Clay Smith 240 duration at .050 and .570 lift on both valves. I know a 19' boat does not sound heavy, but this one is heavier then most which is nice for ripping through the chop. It's a '73 Schiada if you're wondering.