383 10:1 with 516 heads in california?
#371314
07/09/09 07:58 PM
07/09/09 07:58 PM
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Joined: Jun 2006
Posts: 254
Vista, CA
71Chip
OP
enthusiast
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OP
enthusiast
Joined: Jun 2006
Posts: 254
Vista, CA
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A while back I made a thread about helping my friend on his 383. We are using machine tech in oceanside...
They have all the machine work done and all the parts except the 9:1 pistons they were going to use from keith black have been on back order for over a month.
The car is sitting in a borrowed lift stall so we need to get it out of there.
They have the block measured and the factory closed-chambered heads CCed. They said there is a similar price piston in stock (not sure of manufacturer...I can ask) that they know they can get that will put the motor at 10:1.
I went with the reccomendation of one of the guys at IMM and got the comp 265DEH. Car has highway gears and a 2200 stall...will 10:1 work on california 91 octane?
71 Challenger
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Re: 383 10:1 with 516 heads in california?
[Re: 71Chip]
#371315
07/09/09 08:35 PM
07/09/09 08:35 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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With actual measured .035"-.040" quench (piston to head clearance) in each hole, yes
live every 24 hour block of time like it's your last day on earth
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Re: 383 10:1 with 516 heads in california?
[Re: RapidRobert]
#371316
07/09/09 11:16 PM
07/09/09 11:16 PM
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Joined: Jan 2006
Posts: 366
San Gabriel, CA 91775
rexus31
enthusiast
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enthusiast
Joined: Jan 2006
Posts: 366
San Gabriel, CA 91775
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With the crappy gas we get here I would not run a motor at 10:1. What happens if it rattles on 91 octane? Then what? I would go with 9:1 or lower if I was your friend. Before I rebuilt my 383 (with 516's) it was 10:1 with the piston .035 in the hole and it pinged. When I rebiult it I put a set of 452's on which dropped the compression to 8.8:1 which is fine for a street motor. It's got a ton of low end torque and is fun to drive. For me, it's better to be safe than sorry.
2007 Dodge Charger R/T, Road and Track Performance Group, Steel Blue
1965 Chrysler 300 Convertible, 383 4V, 727TF, Factory Air, Spanish Red
1964 Pontiac GTO, Tri-Power, 4 Speed, Grenadier Red
"What ain't no country I ever heard of. They speak English in What?" - Jules Winnfield
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Re: 383 10:1 with 516 heads in california?
[Re: rexus31]
#371322
07/10/09 07:20 AM
07/10/09 07:20 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
With the crappy gas we get here I would not run a motor at 10:1. What happens if it rattles on 91 octane? Then what? I would go with 9:1 or lower if I was your friend. Before I rebuilt my 383 (with 516's) it was 10:1 with the piston .035 in the hole and it pinged. When I rebiult it I put a set of 452's on which dropped the compression to 8.8:1 which is fine for a street motor. It's got a ton of low end torque and is fun to drive. For me, it's better to be safe than sorry.
1) unless it had a pretty decent sized dome or the 516's had a significant amount milled out of them, there's no way you were at an actual 10:1 with the pistons .035" in the hole on a 383.
2) quench plays a very important factor in detonation resistance. with the pistons down that far, even with a steel shim gasktet quench effect is going to be minimal. anecdotally, I have a friend with a 396" stroker SBC, flat tops .014 in the hole or so, right around 11:1 compression with the .050" or so head gasket he was running. had to be VERY selective on gas (could only use shell 93 octane, and even then, the EFI would occasionally pull out timing due to detonation on warm days). he switched to a .028" or so head gasket, his compression actually went up about .2-.3 points, but now he can premium from any gas station around here without detonation....
summitracing has .030 over KB162's in stock to ship today. $323/set.
what's the CC of the heads? assuming 80cc,
KB162's (1.908 CH, 5cc valve reliefs), 6.358" rods, 9.98" deck height, and the Mr. gasket steel shim head gaskets (.020" thick compressed, 4.45" bore) will net you 9.3:1 actual compression ratio, and .044" quench. should work on pump 91. one thought would be you could retard the cam 2-4 degrees. that'll delay the intake closing point, and reduce cyl pressure, and will shift the powerband up slightly.
another piston, speed pro ZL2315F forged are 1.92" CH no valve reliefs, would end up .012" in the hole. I'd probably deck the block that .012", and use .040" gaskets. using the MP composition gasket (.40" thick, 4.38" bore), it still only nets you 9.86:1 compression...not decking, leaving them in the hole gets you 9.6:1 compression, but I think it'll be less prone to detonation with the higher compression/tighter quench
Last edited by patrick; 07/10/09 07:39 AM.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 383 10:1 with 516 heads in california?
[Re: patrick]
#371323
07/10/09 11:05 AM
07/10/09 11:05 AM
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Joined: Jan 2006
Posts: 366
San Gabriel, CA 91775
rexus31
enthusiast
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enthusiast
Joined: Jan 2006
Posts: 366
San Gabriel, CA 91775
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I hear what you guys are saying and you are correct. The reason I like to err on the safe side is I live in CA, a state that probably has the tighest emmissions standars in the country. I woke up one day and premium dropped from 93 to 91 octane. What happens if we wake up on day and they change it again from 91 to 90 or 89? That 9.6:1 motor is going to rattle.
2007 Dodge Charger R/T, Road and Track Performance Group, Steel Blue
1965 Chrysler 300 Convertible, 383 4V, 727TF, Factory Air, Spanish Red
1964 Pontiac GTO, Tri-Power, 4 Speed, Grenadier Red
"What ain't no country I ever heard of. They speak English in What?" - Jules Winnfield
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Re: 383 10:1 with 516 heads in california?
[Re: rexus31]
#371324
07/10/09 12:05 PM
07/10/09 12:05 PM
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Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:
I hear what you guys are saying and you are correct. The reason I like to err on the safe side is I live in CA, a state that probably has the tighest emmissions standars in the country. I woke up one day and premium dropped from 93 to 91 octane. What happens if we wake up on day and they change it again from 91 to 90 or 89? That 9.6:1 motor is going to rattle.
Then you retard the cam or change it altogether. It's much easier than a piston change.
These calculators are a nice pre-planning tool as long as you input your correct/actual values... http://www.wallaceracing.com/dynamic-cr.php Changing the intake closing point changes the results.
I'd shoot for 160-165 cranking pressure and perhaps 7.5 Dynamic with tight quench and iron heads.
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Re: 383 10:1 with 516 heads in california?
[Re: Real-Fury]
#371326
07/10/09 01:41 PM
07/10/09 01:41 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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no, it's not 10:1....I'd be suprised if it's a true 9:1....
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 383 10:1 with 516 heads in california?
[Re: 383man]
#371329
07/12/09 12:56 PM
07/12/09 12:56 PM
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Joined: Jan 2003
Posts: 75,017
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,017
U.S.S.A.
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Quote:
I run 10.0 comp in my iron headed 440. It has 906 heads with KB quench pad pistons for about .042 quench. Runs on 92 with no ping and 38 total timing. Ron
But you are in Maryland and they don't try to pass off goat urine as gasoline.
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Re: 383 10:1 with 516 heads in california?
[Re: patrick]
#371330
07/12/09 12:59 PM
07/12/09 12:59 PM
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Joined: Jan 2003
Posts: 75,017
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,017
U.S.S.A.
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Quote:
no, it's not 10:1....I'd be suprised if it's a true 9:1....
ding ding ding ... WINNER ,
Advertised 10.1 383's are more like 9.2 ACTUAL , you need to have small chambers and pistons that are zero deck ... which requires a sub 79.5 cc chamber ... OR .020 positive deck height, open chamber heads at 79.5 cc AND a steel shim gasket.
DO NOT BELIEVE published chrysler specs
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Re: 383 10:1 with 516 heads in california?
[Re: JohnRR]
#371331
07/15/09 04:03 AM
07/15/09 04:03 AM
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Joined: Jan 2003
Posts: 27,421
Balt. Md
383man
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,421
Balt. Md
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Quote:
Quote:
I run 10.0 comp in my iron headed 440. It has 906 heads with KB quench pad pistons for about .042 quench. Runs on 92 with no ping and 38 total timing. Ron
But you are in Maryland and they don't try to pass off goat urine as gasoline.
I thought it was Moose urine ?    Ron
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