Need more power!!! Help!!
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I have a 5.7 260 in my Chris craft 245 limited,I would like to build a smalll block to make around 400 hp and at least 375 ft.lbs of torque.
I am told I can do it with 350 cubes and don't want to spend the money on a 383 right now.I know ford engines and don't want to spend money until I know what I need.I am going to run a simple head,Vortec,edelbrock,afr 165 ect... I will leave them unported to keep the torque,I am going to run around 9.5;1 in it and plan on max rpm around 4700-5000 as I want to keep my lower end stock right now,the shortblock is in great shape.
I have no idea what a good cam profile is on a small block chevy.Anyone have a good suggestion for a cam to make those power numbers?
I am told I can do it with 350 cubes and don't want to spend the money on a 383 right now.I know ford engines and don't want to spend money until I know what I need.I am going to run a simple head,Vortec,edelbrock,afr 165 ect... I will leave them unported to keep the torque,I am going to run around 9.5;1 in it and plan on max rpm around 4700-5000 as I want to keep my lower end stock right now,the shortblock is in great shape.
I have no idea what a good cam profile is on a small block chevy.Anyone have a good suggestion for a cam to make those power numbers?
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Originally Posted by velocitypwrbtr
245,
You can build a 350 with 400hp easy. It depends on how much you want to refresh the motor. Reliability is the key. Boats are under load most all of the time. I like people who say that they want a 454 to pump out 600hp and last 400 hours. Polish your crank, balance your motor, check your clearances, spacer the carb., put on a set of headers and hope for the best. And it's Martini night. So don't hold my pessimistic attitude against me.
You can build a 350 with 400hp easy. It depends on how much you want to refresh the motor. Reliability is the key. Boats are under load most all of the time. I like people who say that they want a 454 to pump out 600hp and last 400 hours. Polish your crank, balance your motor, check your clearances, spacer the carb., put on a set of headers and hope for the best. And it's Martini night. So don't hold my pessimistic attitude against me.
I know Ford engines and I am just not sure about what it takes to make them numbers in a chevy.I have built many mustangs with stock shortblocks making 400 plus horse and the shortblock held up great,is the merc 350 good for it?
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Vortech heads are nice working heads but your intake that you have now won't work on them. The bolt holes are different.... the bottom end of the motor should hold up fine with the RPM you expecting to run.
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I was looking at the vortec heads but an ad i saw said to have work done to the springs to make them handle more than 400 lift.Is that right? that does not sound like much lift to me even on a stock cam,I know the stock ford engines I start with have 444 lift from the factory.I figure 500.00 for heads and 250-350.00 in new springs and machine work I may as well buy an edelbrock aluminum head or something comparable.
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I have a 355 that was built back in 1995 that supposedly made 424 HP and 445 ft/tq (I have the build sheets and dyno sheets, but was not there which is why I say "supposedly"). It is a standard .030 over 350 with stock steel crank, stock rods with ARP bolts, forged flat tops (Speed-Pro), Dart cast iron heads (not sure which ones other than they have 2.02 and 1.60 int/ex valves), using the stock Mercruiser 1987 EFI manilfold and EFI set up. The cam in this combo works perfectly. The cam is a Crane cam that has been around forever (I have an old 1993 catalog at home with this same camshaft in it... of course back then it was for cars, but they now also include it in their marine section as well so I guess that makes it a marine camshaft now in some peoples mind) it is the HR-284-2S-12 1G.
Here is the link: http://www.cranecams.com/?show=brows...tType=camshaft
This motor is currently turning 5400 rpms with a SS 3 blade and running 70.4 (GPS) in my 20 ft Checkmate, and will still idle around between 450 and 500 rpms without loading up or any signs reversion through the stock cast iron manifolds. Even if I decide to freshen the motor in the future and go with a 383, I will most likely keep this cam but possibly switch to some 1.6 rockers.
Here is the link: http://www.cranecams.com/?show=brows...tType=camshaft
This motor is currently turning 5400 rpms with a SS 3 blade and running 70.4 (GPS) in my 20 ft Checkmate, and will still idle around between 450 and 500 rpms without loading up or any signs reversion through the stock cast iron manifolds. Even if I decide to freshen the motor in the future and go with a 383, I will most likely keep this cam but possibly switch to some 1.6 rockers.
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Thanks,I will look into it.What else is a decent head for the small block that I could run more lift without modifying them?
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I personally really like the Edelbrock ETEC heads, except they are aluminum. If you are running a closed loop or sealed cooling system that would not be a problem, but with a fresh water cooling system I do not know if there would be durability issues with the corrosion aspects of aluminum. With cast iron heads your selection is rather limited. You can get the vortech heads from Scoggin Dickey (SDPC2000.com) already set up with screw in studs, guide plates and better springs but I am unsure of the cost. You could also go with any of the Dart or other brands of cast iron heads. Both the Edelbrock Etecs and the Vortech heads would require use of a vortech style intake manifold, but they will have a flatter TQ curve and make more TQ down low than the other conventional heads which will work with the conventional style intakes. There was at one time a company in Australia I believe (at least I think that was the country) called Pro-Action that supposedly made some fairly awesome heads and they were very reasonable,but they went out of business; however, I have heard that another co. recently purchased their old facility, castings, and everything else and was planning to resume production of their heads, but I have not heard any more news about it in quite some time.