Motor rebuilding. Need advice..
11-24-2014, 07:24 PM
#21
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iTrader: (1)
TooLate
To be frank again, too much of a mess of no information. Engine owner needs to know more specifics before consultation can be performed.
To be frank again, too much of a mess of no information. Engine owner needs to know more specifics before consultation can be performed.
11-24-2014, 07:31 PM
#23
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iTrader: (1)
Having some fun, these Brodix Oval Ports are Huuuuge !
The new BP PB 1204 series features raised 510cc intake ports that flow over 570 cfm and exhaust ports that flow over 350 cfm!
11-24-2014, 07:48 PM
#25
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iTrader: (1)
Peanut Butter Ports are much better than Roval Ports. You should know that UncleDave.
When you call Bob M he'll give you the 'skinny.'
When you call Bob M he'll give you the 'skinny.'
11-24-2014, 11:25 PM
#28
If you start messing with a different cam on a 330hp Merc without changing the stock pistons, then the valves will most likely hit the pistons...and this will also be true if you are adding heads with bigger valves....if I remember correctly, the bigger diameter valves are too big for the valve reliefs in the stock cast pistons and they will hit,....been there done that back in 1984 trying to do all this stuff with a 330hp Merc. Unless of course, Merc has changed some things lately.
If you are looking to add a some power to the 330hp Merc, that may be good about 390-400hp without changing the cam or bottom ends, then do a "bowl port" on the stock heads while paying attention to the "short side radiuses" just under the valve seat, and clean up some of the casting flaws, and do a good 3-angle valve job, add a good aluminum dual plane hi-rise intake manifold, (not a "single plane"), add a Holley 750-800cfm carb, and a good breathing Spark/Flame Arrestor, and some better breathing exhaust manifolds....something like a Stainless Marine brand would be good. And you will notice a little more kick in your engines. If you put a "big" or "huge" head on a stock bottom end 330hp Merc, you will hit soggy bottom and lose power....besides the bigger valves hitting the pistons anyway!
If you are looking to add a some power to the 330hp Merc, that may be good about 390-400hp without changing the cam or bottom ends, then do a "bowl port" on the stock heads while paying attention to the "short side radiuses" just under the valve seat, and clean up some of the casting flaws, and do a good 3-angle valve job, add a good aluminum dual plane hi-rise intake manifold, (not a "single plane"), add a Holley 750-800cfm carb, and a good breathing Spark/Flame Arrestor, and some better breathing exhaust manifolds....something like a Stainless Marine brand would be good. And you will notice a little more kick in your engines. If you put a "big" or "huge" head on a stock bottom end 330hp Merc, you will hit soggy bottom and lose power....besides the bigger valves hitting the pistons anyway!
11-24-2014, 11:36 PM
#29
Just remember, the last I knew, the stock Merc "330hp" valve reliefs in the cast piston was made for a 2.06" Intake valve and only a 1.72" Exhaust valve----a new after market head design will most likely have larger valves sizes than the stock heads that come on the Merc 330hp engine---and you could very well have a problem with the valves hitting the stock pistons.
Yes, there may be some things you can do with the old Merc 330hp, but there simply is not much to work with. The best mods will only yield about 390hp-400hp safely @ about 4600rpm or so.. Has anyone ever mounted a blower on a Stock Merc 330hp with any kind of success and reliability?
Yes, there may be some things you can do with the old Merc 330hp, but there simply is not much to work with. The best mods will only yield about 390hp-400hp safely @ about 4600rpm or so.. Has anyone ever mounted a blower on a Stock Merc 330hp with any kind of success and reliability?
11-25-2014, 05:59 AM
#30
Registered
OP probly has way too much port volume for ANY 454 bottom end. if he insists on staying with those blocks, 496 crank, forged pistons and upgraded rods are the minimum he can get away with with those heads. although i am sure brodix makes a head that would work with 454 bore-stroke he probably went bigger...sounds like everything he has done so far is too much airflow for the rotating assy he has.
