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#2 |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: Who's running the most compression...
I'm running 22 : 1 in my '67 C-30...
But it's a Diesel! ![]() ![]()
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#3 |
Registered User
![]() Join Date: Nov 2006
Location: KINGSPORT,TN.
Posts: 3,035
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Re: Who's running the most compression...
10.1 with iron heads and dist. 36deg. full advance you,ll have to run at least 93 oct. for sure as thats what my 383 is. it will valve rattle like crazy if you dont. 11.1 with alumin heads same thing. 9.1 is all around best for street i think.
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I BELIEVE IN JOHN 3:16 |
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#4 |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: Who's running the most compression...
I've run as high as 10- 10.3 : 1 on a cast-iron headed SBC with a carburetor, but that's pushing it. I'm running a 12.2 : 1 CR 383 in my '82 Z28, but obviously, I'm running race fuel.
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#5 |
Real Projects never die
Join Date: Jan 2007
Location: Lawrence, kansas
Posts: 1,508
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Re: Who's running the most compression...
8.5 to 1 on the maro, oh wait highest? i lose haha
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Ill put it this way, ive got a few lawn ornaments ![]() ![]() My name tag says Ryan KansasTwister On other forums
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#6 |
Registered User
Join Date: Dec 2006
Location: Trinidad, Colorado
Posts: 642
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Re: Who's running the most compression...
My current pulling engine is going into my 68' SWB project.....11:1 on 91 octane w/out problems........but I'm at 7000 feet elevation
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69' 3/4 4X4 470ci BBC 700 HP.... ![]() D60/14bolt 205/465 http://profile.myspace.com/index.cfm...ndid=127691959 |
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#8 |
Registered User
Join Date: Jun 2007
Location: Sweeny,Texas
Posts: 96
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Re: Who's running the most compression...
Hey everyone I'm new to performace stuff. How do you measure comp ratio I have a comp. gauge that I got from a friend.
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#9 |
Registered User
Join Date: Dec 2006
Location: Trinidad, Colorado
Posts: 642
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Re: Who's running the most compression...
Find your chamber size of your heads with your casting number......Go to Mor-Tec.......Then you must know what size/type pistion you're running.
example.....840 BBC iron heads have a 107cc combustion chamber + my L2349F TRW pistons spec sheet says that with 106.9 chambers I'll be around 11:1. If you don't know what piston you have, but the engine is stock, you can get an Idea of what piston was used from some GURU types around the net.
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69' 3/4 4X4 470ci BBC 700 HP.... ![]() D60/14bolt 205/465 http://profile.myspace.com/index.cfm...ndid=127691959 |
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#10 |
huh ???
Join Date: Nov 2002
Location: Fredericksburg,Va.
Posts: 3,369
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Re: Who's running the most compression...
That's what mine was when I had the 6.2 in my 72...
Chuck
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90 Blazer Silverado 350w/ 700R4 and 32" Kelly's "I am a bomb technician. If you see me running try to keep up!" |
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#11 |
Registered User
Join Date: Apr 2007
Location: NSW, Australia
Posts: 205
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Re: Who's running the most compression...
I'm running propane I think my motor has something like 10:1 compression, and it runs great I've been told that 13:1 is acceptable with propane without any issues
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#12 |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,859
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Re: Who's running the most compression...
18:1 in my 6.5TD.They actually can be made to run better by lowering from 22:1,sounds silly,right?
I`m picking up my fresh 327 today.It will be about 9.5 to 9.7:1 w/iron heads.I may get away with regular.It will be awhile before it sees service to find out.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#13 |
Official Site Guitar Shredder
Join Date: May 2006
Location: Oz
Posts: 3,955
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Re: Who's running the most compression...
9.5 but im going to a vortec S trim over the winter, my lower end is basically stock ZZ3 but i have had a ton of head work,( port polish port matched to my intake three angle vavle job dual springs, 2,02 1.60 valves and ported and ploshed my intake lil bigger cam (roller) , and of course my erson (extremly loud ) gear drive ,< i think it steals ponies though.... lol but it sounds awsome.........oh i lose
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#14 |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: Who's running the most compression...
Not silly at all. You can turn the boost on up with the 18:1's w/o blowing head gaskets and melting holes in pistons!
__________________
'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#15 |
Registered User
Join Date: Feb 2001
Location: Wetumpka, Al, U.S.
Posts: 8,891
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Re: Who's running the most compression...
I have 14 to 1 pistons in my junk but I run race gas! I will run as low as 112octane without the spray but only 116 to 118 when its on the bottle!
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Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole! |
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#16 |
Fabricate till you "puke"
Join Date: Jun 2002
Location: Ill
Posts: 9,403
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Re: Who's running the most compression...
I run 9.8 on my alum headed 383, with 34 degrees of mechanical advance ,all in @ 2700 & 12 additional degrees in the advance can. Its fine on 91 octain fuel, but will ping a trace on 89 pulling a steep hill.
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69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... |
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#17 |
Senior Member
Join Date: Nov 2005
Location: AL
Posts: 2,519
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Re: Who's running the most compression...
I will be running about 11.5:1 on my iron ls1.
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#18 |
Registered User
![]() Join Date: Feb 2007
Location: Star Valley, WY
Posts: 2,038
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Re: Who's running the most compression...
8.9 cr in my MKIV block. a bit low for aluminum heads but im building a decent amount of cylinder pressure to make the best of my lower duration cam and flattop pistons.
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Steve 1971 GMC Longbox. Full Roller Stroker 489 w/ FiTech EFI, Chris Straub Cam/NV4500/205/D60/14B w. Grizzly Locker and 4.11's. 2" Lift on 33's |
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#19 | |
Texas Big Wig
Join Date: Jan 2007
Location: Mineola, Texas
Posts: 5,620
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Re: Who's running the most compression...
Quote:
Are you LP only or can you still run off gas when you need too ??? |
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#20 |
Registered User
Join Date: Feb 2001
Location: Wetumpka, Al, U.S.
Posts: 8,891
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Re: Who's running the most compression...
my buddy had a 13 to 1 440 in a 70 duster but we had to mix av gas and super! It was one fast car for the street!
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Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole! |
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#21 |
Registered User
Join Date: Aug 2007
Location: greenville,ms.
Posts: 47
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Re: Who's running the most compression...
I've got a 388 with 10.6-10.7, sportsman heads but it lives on 100 octane low lead avgas. It realy likes it.
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#22 |
18 Till I Die
Join Date: Mar 2005
Location: Alberta, Canada
Posts: 1,522
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Re: Who's running the most compression...
454 BBC LS7 12.25:1 crate engine with port and polished heads/matching intake and a 850 Holley. Premium and avegas 60/40 mix or premium and octane boost when the drum runs dry.
Kind of a crappy clip http://www.youtube.com/watch?v=5ru1cCe62JQ
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2011 GMC Acadia 1969 GMC BBC LS7 2007 GMC Crew Duramax 1987 Camaro Iroc 350 Tuned Port Injection 42000Km 1987 Chevrolet Silverado 350 TBI 1987 Chevrolet Silverado 350 TBI(yes 2) Take me drunk, I'm too home... ![]() |
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#23 |
Registered User
Join Date: Jul 2006
Location: Fair Oaks, CA
Posts: 475
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Re: Who's running the most compression...
You can run propane at 13 to or 14 to 1 no problem in fact it will help maximize power to fuel consumption raising compression, propane is 105 octane and loves high comp.
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1968 Short Fleet 350/700r4 http://67-72chevytrucks.com/vboard/s...d.php?t=249435 1997 Bagged XtdCab Vortec350/4L60e http://67-72chevytrucks.com/vboard/s...44#post2286144 1993 XtdCab Longbed 4x4 6.5Turbo/NV4500 "Daily Driver" 1985 Toyota XtdCab 4x4 22re/W-56/Dual T-cases, Doug Thorley Header, Homebrew front and rear spring packs, Tons of Mods to suspension and drivetrain, 35" boggers, coming soon ARB's and 5.29's, Possible 4.3/700r4 swap |
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#24 |
Senior Member
![]() Join Date: Jul 2006
Location: Leander, Texas
Posts: 850
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Re: Who's running the most compression...
10:1, no problems on pump gas at 12 degrees initial. I can bump up the timing some with some 104 race fuel in it.
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#25 |
Registered User
Join Date: Jul 2007
Location: new mexico
Posts: 10
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Re: Who's running the most compression...
i had a det of 601 heads off a 305 and put them on my 355 race engine. ran 11:1 ran super unleaded and av fuel 50/50 around 32 degrees advance. dirt cirlce 6500 rpm. hottest would run was 230 degrees no problems. combustion chambers were 55cc and flat top 2 brow pistons.
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