478 Hemi
#1996955
01/23/16 01:22 PM
01/23/16 01:22 PM
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Joined: Mar 2010
Posts: 213 Canada
Cape
OP
enthusiast
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OP
enthusiast
Joined: Mar 2010
Posts: 213
Canada
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Hey everyone. I have a Hemi that's more set up for drag racing it's a 12:5.1 cp Pistons the cam is huge a solid roller 800 lift 292int 294ex. Heads are stock Mopar crate motor heads with better valves and comp springs the heads are cast. the block is a world block bored 30 over. My question is I want to make it more street and was wondering what you would do to it? Can I use the Pistons that are in it on pump gas? I don't really want to have them cut to make it work. Cam selection is up to you. If I forgot anything let me know. Thanks. I guess my question is is it possible to use this short block and cast heads on pump gas. But changing cam and springs and valves. Thanks
Last edited by Cape; 01/23/16 01:37 PM.
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Re: 478 Hemi
[Re: Cape]
#1996990
01/23/16 02:05 PM
01/23/16 02:05 PM
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Joined: Jan 2005
Posts: 4,243 Charlotte, North Carolina
sgcuda
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master
Joined: Jan 2005
Posts: 4,243
Charlotte, North Carolina
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That's a lot of compression with cast iron heads for pump gas. I don't think you could get away with a thicker head gasket to kill enough compression. If the domes are solid, you might be able to mill some off the top. Lowering cam duration is only going to raise cranking compression at this point, and make matters worse for using pump gas. E85 fuel might be an option, but that depends on availability in your area.
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Re: 478 Hemi
[Re: Cape]
#1997105
01/23/16 04:43 PM
01/23/16 04:43 PM
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Joined: May 2004
Posts: 12,388 Taxes & Virus's R-US, NY
Dragula
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Taxes & Virus's R-US, NY
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Only things I would change is reduce the compression 1pt down to 11:5 with Cometec gaskets, and switch to a milder cam under .740 lift....That's it really. Hemi's will tolerate a lot of compression on 93. What intake and carb(s)?
Last edited by Dragula; 01/23/16 04:44 PM.
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Re: 478 Hemi
[Re: Cape]
#1997635
01/24/16 01:31 PM
01/24/16 01:31 PM
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Joined: May 2004
Posts: 12,388 Taxes & Virus's R-US, NY
Dragula
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The intake looks just like the Barton one but a 4150 one. The rods are stock size 426 rods.are you talking about getting rid of my single plane for a duel plane? No, not exactly...It was a heavily modified 4150 dual plane, and they made it into a 4500 single plane...I would never run a dual plane on anything unless its the only option for hood clearance, and then I usually turn it into a single plane as best as I can...The Modman is also an option. Found it....Indy Heads catalogue pg 22, although it states its still a dual plane. The ones I have seen in use were not. The inside was all gutted out to make a low profile single plane... http://www.indyheads.com/images/22.cat2014.pdfIf hood clearance isn't an issue, I would go with stay with what you have...Plugs have looked the best with the Indy or the Barton ones we have tested.
Last edited by Dragula; 01/24/16 01:34 PM.
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Re: 478 Hemi
[Re: Cape]
#1998284
01/25/16 12:02 PM
01/25/16 12:02 PM
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Joined: Jan 2003
Posts: 13,365 Marion, South Carolina [><]
an8sec70cuda
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I Live Here
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Marion, South Carolina [><]
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Dragula...the intake he has looks just like the Barton single plane, it's just a 4150 flange. Sold as a MP part and has "MOPAR" cast where the typical Barton logo would be. You should be able to redo the flange on this manifold for the 4500 pattern. It's shorter than the Barton manifold and I have seen the Barton manifold cut down to fit under the hood.
Cape...hemis can tolerate a lot of compression w/ pump gas. There's a few around 12:1 doing it. I'd try a thick head gasket and get a custom cam ground for it. Call Dwayne Porter for a cam. 802-951-1955
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: 478 Hemi
[Re: 605ply]
#1998677
01/25/16 10:10 PM
01/25/16 10:10 PM
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Joined: May 2004
Posts: 12,388 Taxes & Virus's R-US, NY
Dragula
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I Live Here
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another option with intake is two fours..they'd fit under your hood...just found a stage V for500 cdn on kijiji......but edelbrock makes2x4 manifold, summit price us477$(if memory serves price has just gone up 50$+)..edelbrock carbs are cheap and plentiful and work quite well ...dominator won't work on a modman.. Again, get one of those all milled out like a single plane, or a modman....
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Re: 478 Hemi
[Re: Jimi_Vignogna]
#1999464
01/27/16 12:12 AM
01/27/16 12:12 AM
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Joined: May 2004
Posts: 12,388 Taxes & Virus's R-US, NY
Dragula
I Live Here
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I Live Here
Joined: May 2004
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Taxes & Virus's R-US, NY
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every street hemi with cast iron heads I ran @ 12.5 to 1 on pump gas. the only aluminum head engine was 13.2 to one on pump gas. never had a problem They will tolerate a lot more than most. I never ran iron heads on pump gas at over 12:1, but the aluminum's will definitely tolerate 12:1.
Last edited by Dragula; 01/27/16 12:13 AM.
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