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Make sure it has plenty of fuel at 9.5:1 with iron heads.
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Originally Posted by jeff1000man
(Post 3271153)
If you deck those heads, you are going to loose a lot of valve lift that you really need to get those engines to breath.
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Those cams are awful. They have less duration and lift than a 415hp 502 efi. Most rv cams have more lift and duration. A good cam for stock rectangular port heads is the Crane 651. It is 244 int. / 256ex. duration @ .050, .630 / .630 lift. this cam will make 575-600 hp and rev to 5400-5600. For any more hp, you will need aftermarket heads.
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Originally Posted by Rebel_Heart
(Post 3271113)
Jim Valako is the man when it comes to porting aluminum heads. He did a great job on my Dart Pro Ones. I'm running 1050s on my 540s.
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Originally Posted by Rookie
(Post 3271217)
Could you explain this to me? I see that your valves will be closer to the piston but the lift and rocker ratio is still the same. The mechanics that lift the valve are the same.
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you guys are helping me a ton. thanks for all the info.
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The piston to valve clearence with those pistons is quite large. Easily enough for any cam you would want in a marine engine. To answer the original question, I bet the hp peak would be 4600 using the parts specified. And I would guess that it makes about 450 hp but about 700 ft.lbs. of torque.
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Originally Posted by PatriYacht
(Post 3271404)
The piston to valve clearence with those pistons is quite large. Easily enough for any cam you would want in a marine engine. To answer the original question, I bet the hp peak would be 4600 using the parts specified. And I would guess that it makes about 450 hp but about 700 ft.lbs. of torque.
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Originally Posted by PatriYacht
(Post 3271224)
Those cams are awful. They have less duration and lift than a 415hp 502 efi. Most rv cams have more lift and duration. A good cam for stock rectangular port heads is the Crane 651. It is 244 int. / 256ex. duration @ .050, .630 / .630 lift. this cam will make 575-600 hp and rev to 5400-5600. For any more hp, you will need aftermarket heads.
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I just looked a second time at the cam card. The cam card doesn't match the wording above it. A bit of confusion in that catalog. The cam card looks better.
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