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  #1  
Old 05-24-2008, 05:12 PM
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ky509 ky509 is offline
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Default 383ci L2315 PISTONS AND 906 HEADS

What would the compression be in a 383 using L2315 .030 pistons and a set of 906 heads with a thick gasket. Thanks in advance. Also, where could I find info giving combinations and options for compression ratios on mopars?

Thanks
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Old 05-25-2008, 12:22 AM
Walkercolt Walkercolt is offline
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A phone call to Hughes Engines or Ray Barton will give you more information than you can handle, although you may not like what they tell you, about what combinations work and which ones don't. They may tell you ditch the 906 heads if you're running pump gas. You need 21st Century tech heads designed to make power from the swill we call gas today. The new Edelbrock's leap to mind, but that will be your choice and budget.
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Old 05-25-2008, 12:36 AM
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ehostler ehostler is offline
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Not knowing anything about your engine and what you've done to the heads, it would just be a ballpark guess. Here is a great calculator - http://kb-silvolite.com/calc.php?action=comp
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Old 05-25-2008, 06:59 PM
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Default 906 heads V Stealth heads

Quote:
Originally Posted by Walkercolt View Post
A phone call to Hughes Engines or Ray Barton will give you more information than you can handle, although you may not like what they tell you, about what combinations work and which ones don't. They may tell you ditch the 906 heads if you're running pump gas. You need 21st Century tech heads designed to make power from the swill we call gas today. The new Edelbrock's leap to mind, but that will be your choice and budget.

Its a shame to have to ditch these 906 heads being that some one has poured a bunch of dollars into them and they are practically new. But on the other hand I`m smart enough to know when something just isn`t going to work. 440 source is making a set of aluminun heads they call STEALTH HEADS. ready to bolt on for 900.00 + 55.00 freight. Tuesday I`m going to see if they will work with the L2315 pistons that came with the block. Per 440 source the new heads have about 84 cc`s and they are closed with a quench surface. In fact below are the specs I gleaned from their web site. Its hard to beat the deal, great heads at a great price and lose the weight on top of all the other bennies. Kind of hard to go wrong.

Stealth heads
Cylinder Head Technical Specs:


Cylinder Head Technical Specs:
Intake Port Flow (at peak ~600 lift):............................ 290CFM @ 28" of water
Intake Port CC:............................................... ............ 212CC
Intake Valve Head Size:............................................. . 2.14"
Intake Valve Stem Size: ...........................................11/32", undercut near valve head.
Intake Valve Guide Type: ..........................................530" OD Manganese Bronze
Intake Valve Seals Type:............................................. . Positive Locking type, maintains contact at all times with the valve -
- and guide, reduced diameter compatible with most dual valve springs.
Intake Valve Type:............................................. ...... 1 piece forged 21-4N stainless, swirl polished heads, hardened tips.
Intake Valve Locks............................................. ....... 7 degree, single groove, chrome-moly steel, case hardened.
Exhaust Port Flow (at peak ~600 lift):............................ 220CFM @ 28" of water
Exhaust Port CC: 72CC
Exhaust Valve Head Size: ............................................1.81"
Exhaust Valve Type: .................................................. .1 piece forged 21-4N stainless, swirl polished heads, hardened tips.
Exhaust Valve Locks............................................. .. 7 degree, single groove, chrome-moly steel, case hardened.
Exhaust Valve Stem Size ..........................................11/32", undercut near valve head.
Exhaust Valve Seals Type: ......................................Positive Locking type, maintains contact at all times with the valve and-
- guide, reduced diameter compatible with most dual valve springs.
Exhaust Valve Guide Type: .......................................530" OD Manganese Bronze
Valve Spring Type: .................................................. Single with Damper
Valve Spring Closed (seat) Pressure: Approx. ............130 pounds @ 1.875" installed height
Valve Spring Open Pressure Approx. ......................330 pounds @ 1.275" (.600" lift.)
Valve Spring Inner Diameter:................................... 1.050"
Valve Spring Maximum Lift:.................................... .600"
Valve Spring Coil Bind Height: ...............................1.130"
Valve Spring Outer Diameter: .................................1.550"
Valve Spring Free Height .......................................2.400"
Valve Spring Installed Height: ...............................1.875"
Valve Spring Wire Diameter:............................. .202"
Valve Spring Number of Coils:............................. 5.5
Deck Thickness: ................................................62 5" Chamber Volume: 84CC
Chamber Type:............................................. .... Closed (with quench surface)
Weight (bare):........................................... ........ 22 pounds
Weight (assembled): ..........................................29 pounds
Aluminum Type.............................................. .. A-356
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Old 05-25-2008, 07:01 PM
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Quote:
Originally Posted by ehostler View Post
Not knowing anything about your engine and what you've done to the heads, it would just be a ballpark guess. Here is a great calculator
Thanks for the link. I just do not have enough info on the eng i`m working on th use it. Maybe when I get all my S together I can try it out.
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Old 05-25-2008, 08:46 PM
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ehostler ehostler is offline
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Why ditch the 906 heads? especially if they have had lots of work done to them? Is it just because one person tells you to ditch the 906 heads?

Think about it this way. On one hand, you already have the 906 heads that are setup and ready to go or you can spend $900 + shipping for a pair of aluminum heads. Unless you are building a race motor, I really don't see you gaining much on the expense of $900.
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Old 05-25-2008, 11:51 PM
Walkercolt Walkercolt is offline
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Ed's got a good point. I don't know how much you want to spend and how much power you want out of your 383. I've seen people spend lots of money on factory iron heads(not just on BB Mopars) and be very dissapointed at the results. It's just that you're working with 30-40 year-old technology, and pump gas is getting worse everyday. Just worry that you might knock holes in your new pistons. Mopar Muscle took their "cheap-build" 400 and put Edlebrock heads on it and gained over 70HP on regular unleaded over 92 octane Rocket Brand race gas, and cranked in 4* more advance on the timing and no knocks, no pings, and gained fuel mileage...alot. Fine tuning the carb became much easier. They thought they were worth the money, even if you're on a tight budget. Just thought I'd throw it out there.
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Old 05-26-2008, 11:19 AM
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Quote:
Originally Posted by ehostler View Post
Why ditch the 906 heads? especially if they have had lots of work done to them? Is it just because one person tells you to ditch the 906 heads?

Think about it this way. On one hand, you already have the 906 heads that are setup and ready to go or you can spend $900 + shipping for a pair of aluminum heads. Unless you are building a race motor, I really don't see you gaining much on the expense of $900.
Well the more research I do the more practical the aluminum heads look for my intended purposes. I am going to be street and strip. I do want to dump all the weight I can. I also want all the compression I can get on pump gas with out the knocks and pings. You might say I want my cake and eat it to.

This 383 is only a temporary engine. Down the road there will be a 500 + ci motor built for it. I intend using aluminum heads on the big engine so this way i`ll already have them.

Actually I have never been a big believer in open chambered heads on any engine. In fact all my chevys have the old double humpers on them. These 906`s are nice heads but imo the builder would have been better of working up a set of 915`s.

I have decided on the aluminum heads for several reasons and one is like the
Walkercolt mentioned, they are old technology, no arguing that. ALUM =`s Less weight, better quench, better flow and they will be brand new. Plus I can probably get half of the cost of the aluminum heads for the 906`s which I have little to nothing in, Putting me into a nice set of up dated heads for half the cost of retail. I`m better off down the road when the 440 block gets built. But in the nean time the 383 will be strong enough to have a little fun with. The 383 @ .030 over bore = 389 , good heads, some hooker headers, decent cam and 6 pak system and I can have some fun with it till the monster motor is completed. If anything is left of the 383\389 then I can sell it. Anyhow every thing I read indicates don`t mess with the 906`s due to poor squish quench. Plus you have to admit, a grand for a good set of aluminun heads that are new and ready to bolt on, thats a heck of a deal. People are giving more for used aluminun heads, and we both know that 440 source will go up on that price. It would be dumb of me to wait and pay more for them later, knowing that aluminum is what I want in the end.
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