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383 Quench Question
#925987
02/11/11 12:35 AM
02/11/11 12:35 AM
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JoesMopar
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Can anyone tell me the best way to get quench from a 383 using the 906 heads? I looked at the Edelbrock closed chamber heads on Summit and I don't know if it was a misprint or what but it listed the bare 84cc heads for $900+ each. I think I want to use the 906 heads anyway, and if I don't like them I can always change things later on. I'm not building a racing engine, just a nice street engine. I'm shooting for 375-400HP. If it helps my other list of parts will be a Performer RPM, 750 carb (not sure which), XE 274 cam and matching springs, stock rockers, MP ignition, Dougs headers, and 2 1/2" exhaust. Not sure on the pistons, that depends on what you guys recommend for the 906's. The car also has a 727/3.23 SG set up. Thanks 
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Re: 383 Quench Question
[Re: JoesMopar]
#925988
02/11/11 12:49 AM
02/11/11 12:49 AM
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1_WILD_RT
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http://www.summitracing.com/parts/EDL-60929/$735 ea for complete head assemblies If you build it with 906's & try to obtain quench you'll need quench pad pistons designed to work only with open chamber heads...The short block won't accept closed chamber heads later without a piston swap... Plus to obtain quench with your 906 heads is gonna require machining each chamber to equalize the depth plus machining each piston the set the quench pad height... It would be cheaper to build a zero deck short block & buy closed chamber heads whether you get Edelbrocks or Stealths...
"The Armies of our ancestors were lucky, in that they were not trailed by a second army of pencil pushers."
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Re: 383 Quench Question
[Re: 1_WILD_RT]
#925990
02/11/11 12:56 AM
02/11/11 12:56 AM
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I just searched for those before I posted this and didn't see them. Thanks for the link. This is what I found before http://www.summitracing.com/parts/EDL-609219/So the KB 400's will not give you any quench with the 906's? With a flat top, I could always figure what the comp height is and just have the block zero decked right?
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Re: 383 Quench Question
[Re: JoesMopar]
#925991
02/11/11 12:58 AM
02/11/11 12:58 AM
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1_WILD_RT
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No! Leave those KB400's out of your motor or you'll be doomed to a 8.2 C/R...
"The Armies of our ancestors were lucky, in that they were not trailed by a second army of pencil pushers."
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Re: 383 Quench Question
[Re: 1_WILD_RT]
#925994
02/11/11 01:48 AM
02/11/11 01:48 AM
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To give an idea of how hard it is to get decent compression in a 383 with a piston that gives true zero deck height, a .039 gasket & a chamber volume of 84cc you'll have right at 9.5-1 C/R & you really need a small valve notch which would drop the C/R down to 9.25.... And with aluminum heads & good quench you really want to be at 10.5+ ........... To get there with 4cc valve notches in the pistons would require cutting the chamber volume to 70cc... The short stroke makes chamber volume critical... Another reason why guys build strokers..
"The Armies of our ancestors were lucky, in that they were not trailed by a second army of pencil pushers."
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Re: 383 Quench Question
[Re: 1_WILD_RT]
#925995
02/11/11 10:13 AM
02/11/11 10:13 AM
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the frozen wastes...
Pale_Roader
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Quote:
To give an idea of how hard it is to get decent compression in a 383 with a piston that gives true zero deck height, a .039 gasket & a chamber volume of 84cc you'll have right at 9.5-1 C/R & you really need a small valve notch which would drop the C/R down to 9.25.... And with aluminum heads & good quench you really want to be at 10.5+ ........... To get there with 4cc valve notches in the pistons would require cutting the chamber volume to 70cc... The short stroke makes chamber volume critical... Another reason why guys build strokers..
If you're spending money on heads for this combo, the Brodix B1BS has 65-66cc chambers with a very good design that will net you some compression with zero deck. Last i checked they were around a couple grand a pair... not much more than the Edelbrocks, and a way better head overall...
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Re: 383 Quench Question
[Re: Pale_Roader]
#925996
02/11/11 10:29 AM
02/11/11 10:29 AM
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71383beep
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You could just go find some closed chamber 516 or the even better 915 head if you're looking to keep your project cheap. You would need to put a bit more $$$ into the 516s but they can be made to work.
I have 396/430 hp/tq with a set on my 383. I had much less with the vaunted boat anchor 906's on there before for the exact reasons posted above.
let the magazine guys have the 906's and other open chamber heads. If you want compression and quench closed chamber is the only way to go...IMHO
Last edited by 71383bee; 02/14/11 08:21 PM.
'73 GK6 Challenger Rallye - 340 4-Speed
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Re: 383 Quench Question
[Re: 1_WILD_RT]
#925997
02/11/11 10:35 AM
02/11/11 10:35 AM
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JohnRR
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Quote:
No! Leave those KB400's out of your motor or you'll be doomed to a 8.2 C/R...
Nope , the 400's will give you over 9 , it's the flat top 162 that will create a low compression pig .
As stated you can't get quench with 906's unless you get a custom piston or mill the 906's into a closed chamber.
Just buy a closed chamber head if you have a set of 906's that need to be rebuilt . 
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Re: 383 Quench Question
[Re: JohnRR]
#925998
02/11/11 10:46 AM
02/11/11 10:46 AM
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cjs69mope
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My Dads 383 has kb 400 pistons , 84cc edelbrocks heads and .039 gasket the motor has been decked so the piston is .005 inthe hole and the final calculated compression was 10.2-10.4 to 1 . The motor runs strong with rpm intake and 750 holley hp vac sec carb and mp electronic ignition Chrome box . with the comps cams 275hl cam strait up .and hedman headers with 2.5 exhaust . = good fun burning the tires with quick stab of the throtle  he has even been pulled over for it and really was not trying to rip them up at all so he says 
1969 Dodge Charger
1969 Dodge Superbee
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Re: 383 Quench Question
[Re: JoesMopar]
#926001
02/11/11 09:04 PM
02/11/11 09:04 PM
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JohnRR
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Quote:
Ok, I know I'm changing the direction here.
Lets say I get a pair of KB flat tops, zero deck the block, and use the closed chamber (84cc) Edelbrock heads....would that be decent as far as compression and quench? With a zero deck the piston should be as far away from the head as whatever the compressed thickness is of the head gasket I'm using right? So how about this plan? Now I just need a head gasket thickness.
Do yourself a favor and do not buy the KB162's , they [self censored] , lower in the hole than they should be and a CANYON for a valve relief , spend a little extra money and buy a set of speedpro 2315 or a few more and get a set of diamond 383 pistons if you need valve reliefs ...
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Re: 383 Quench Question
[Re: JoesMopar]
#926003
02/11/11 09:13 PM
02/11/11 09:13 PM
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ahy
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Quote:
Ok, I know I'm changing the direction here.
Lets say I get a pair of KB flat tops, zero deck the block, and use the closed chamber (84cc) Edelbrock heads....would that be decent as far as compression and quench? With a zero deck the piston should be as far away from the head as whatever the compressed thickness is of the head gasket I'm using right? So how about this plan? Now I just need a head gasket thickness.
With that setup and a common head gasket at .040" thickness you would have excellent quench and around 9.0:1 compression. If you had the heads milled to 71 cc's - which is quite feasible - you would be at about 10.25 CR. About ideal in my book for a slightly conservative mild performance pump gas engine.
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Re: 383 Quench Question
[Re: RapidRobert]
#926004
02/11/11 09:57 PM
02/11/11 09:57 PM
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JohnRR
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Quote:
Quote:
With a zero deck the piston should be as far away from the head as whatever the compressed thickness is of the head gasket I'm using right? So how about this plan?
(1) right and a 35-39 thou gasket will get your quench spot on (w piston rock potential measure it carefully/meticulously) (2) A true flat top at zero deck may have too high of a CR, A KB type piston that has a flat plateau to get the quench and the perimeter is lower plus the valve reliefs will most likely be a more street friendly plan unless you're building a killer w a radical cam and racing gas to keep it from pinging
KB doesn't make a quench pad piston for a 383 , which is absolutely stupid on their part.
I would also think a person would have some really loose fitting pistons to have piston rock that would contact the head using a .039 thick gasket ...
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Re: 383 Quench Question
[Re: HYPER8oSoNic]
#926006
02/12/11 03:07 AM
02/12/11 03:07 AM
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JohnRR
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Quote:
Do your RESEARCH on ALL of these routes (ideas)for more
compression. Then decide which is feasible to you in effectively giving the compression you need for the LEAST amount of cash outlay.
it's going to end up costing alot whether he gets a diamond or a flat top KB , with the KB you have to cut more off the block and the heads because of that canyon ...
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