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Open or Closed Chamber Cylinder Heads? #1697587 11/11/14 07:27 PM 11/11/14 07:27 PM
Joined: Apr 2012 Posts: 1,562 Macomb, MI V vinnyd76 OP pro stock
vinnyd76 OP pro stock V Joined: Apr 2012 Posts: 1,562 Macomb, MI	I have a bare 440 HP engine block that will be bored .020 or .030 over (magnaflux process already complete - block currently standard bore). No components have been purchased thus far. I'm considering forged pistons and 906 heads. The vehicle that this will be installed in is TBD at this point. However, 60% of time the vehicle will be driven to around town to car shows, cruising, etc... I was told that I should change the main cap bolts to studs (better clamp load, long term durability over original bolts). Thoughts? I welcome your thoughts on components, compression ratio, etc...

Re: Open or Closed Chamber Cylinder Heads? [Re: vinnyd76] #1697588 11/11/14 07:30 PM 11/11/14 07:30 PM
Joined: Jan 2003 Posts: 15,976 Chilliwack B.C. Canada R RUNCHARGER I Live Here
RUNCHARGER I Live Here R Joined: Jan 2003 Posts: 15,976 Chilliwack B.C. Canada	Main bolts are fine. I would right away figure on a closed chamber head and pistons that give you quench. So the 906's don't fit into that plan. I prefer forged pistons. Sheldon

Re: Open or Closed Chamber Cylinder Heads? [Re: vinnyd76] #1697589 11/11/14 07:57 PM 11/11/14 07:57 PM
Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,040 Lincoln Nebraska	main bolts/hyper pistons. Quench is better but are you considering 67 915 heads or source ($$$) or eddy ($$$) closed chamber heads to get it. live every 24 hour block of time like it's your last day on earth

Re: Open or Closed Chamber Cylinder Heads? [Re: RapidRobert] #1697590 11/11/14 08:30 PM 11/11/14 08:30 PM
Joined: Jun 2008 Posts: 3,916 usa L lewtot184 master
lewtot184 master L Joined: Jun 2008 Posts: 3,916 usa	kb184 pistons for open chamber heads and pump gas.

Re: Open or Closed Chamber Cylinder Heads? [Re: lewtot184] #1697591 11/11/14 10:03 PM 11/11/14 10:03 PM
Joined: Jan 2007 Posts: 7,664 IN A ahy master
ahy master A Joined: Jan 2007 Posts: 7,664 IN	Lots of nice engines have been built that way. With an open chamber head (no quench) compression in the low to mid 9's usually works well without detonation. Studs do help retain the main caps but in a mild engine not too important. When adding studs, line hone is recommended to bring the bearing bores back to round with the higher clamp load. On the heads... if you have a set of 906's in good condition makes sense to use them. If you don't buying and rebuilding the heads or buying a quality re-built set will cost nearly as much as or maybe more than a new set of aluminum heads. My suggestion would be use aluminum (eg Eddy or Stealth) closed chamber heads and build so the piston is at zero deck. With a common .040" gasket you will have perfect quench. You can push compression to 10-10.5, get more power and better mileage. Getting block top decks machined square and deck height measured by your machinist is the first step in a "quench build".

Re: Open or Closed Chamber Cylinder Heads? [Re: ahy] #1697592 11/12/14 05:45 AM 11/12/14 05:45 AM
Joined: Apr 2012 Posts: 1,235 Phoenix, AZ Jjs72D Deep in the closet
Jjs72D Deep in the closet Joined: Apr 2012 Posts: 1,235 Phoenix, AZ	Seems to me that some of the considerations will depend on the vehicle it will power. A small A body may need to use cast iron manifolds for clearance so that impacts the choices for cam and compression ratio. The Road Runner or Challenger models really open up exhaust choices so things are easier to determine.

Re: Open or Closed Chamber Cylinder Heads? [Re: ahy] #1697593 11/12/14 06:23 PM 11/12/14 06:23 PM
Joined: Feb 2003 Posts: 21,318 Manitoba, Canada DaytonaTurbo Too Many Posts
DaytonaTurbo Too Many Posts Joined: Feb 2003 Posts: 21,318 Manitoba, Canada	If you do a set of aluminum closed chambered heads with a piston that sits flush with the deck, you can use a standard .040 compressed thickness head gasket. This combination will get you a quench build which will allow you to run a little more compression on pump gas and make a little bit better power. An aluminum headed quench built 440 with a mild cam can do 10.5 compression on pump gas where an open chambered 906 iron headed 440 would top out in the low 9's compression range. This is the preferred way to setup your engine these days, but by no means the only way. Another consideration is cylinder heads. If you have a junker set of 906's that need to be rebuilt, then buying a set of aluminum aftermarket heads like the edelbrocks or 440source's starts to look really attractive because the price to rebuild a set of stockers is not cheap, not to mention the benefits of the extra flow and improved cylinder head design and materials of the aluminum heads. If you have a good set of iron heads already done up, then you can look at a set of dome pistons you can grind for quench.

Re: Open or Closed Chamber Cylinder Heads? [Re: DaytonaTurbo] #1697594 11/13/14 02:39 AM 11/13/14 02:39 AM
Joined: Jan 2003 Posts: 27,421 Balt. Md 3 383man Too Many Posts
383man Too Many Posts 3 Joined: Jan 2003 Posts: 27,421 Balt. Md	Quote: If you do a set of aluminum closed chambered heads with a piston that sits flush with the deck, you can use a standard .040 compressed thickness head gasket. This combination will get you a quench build which will allow you to run a little more compression on pump gas and make a little bit better power. An aluminum headed quench built 440 with a mild cam can do 10.5 compression on pump gas where an open chambered 906 iron headed 440 would top out in the low 9's compression range. This is the preferred way to setup your engine these days, but by no means the only way. Another consideration is cylinder heads. If you have a junker set of 906's that need to be rebuilt, then buying a set of aluminum aftermarket heads like the edelbrocks or 440source's starts to look really attractive because the price to rebuild a set of stockers is not cheap, not to mention the benefits of the extra flow and improved cylinder head design and materials of the aluminum heads. If you have a good set of iron heads already done up, then you can look at a set of dome pistons you can grind for quench. This is good advise I completely agree with. I ran 906 heads back on my old 440 but I do my own head work (or did until my back went out) and I could rebuild my iron heads myself and save a ton of money but unless you do your own head work its not much if any more to just go with aluminum heads like the Stealth or Eddy's and if you want to go faster and spend more you can go to Indy or Victors or any of a few brands out there. But in todays market its hard to beat the aluminum heads with closed chambers to build a nice quench eng. Ron

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