C5Z 430" build thread... ERL, PRC, SRD, DLRE.
07-13-2016, 08:10 PM
#42
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At this point it's not a breathing issue, it's a valve float issue. I'll be back with results soon. And remember, these are box stock SMALL BORE PRC 265's... I have half an urge to pull the heads and open them up another 10cc on both sides. This thing is way surpassing what I thought it was going to make on torque. I could be wrong but I think it was at 500ft lbs at 3k rpm.
07-14-2016, 01:33 PM
#43
At this point it's not a breathing issue, it's a valve float issue. I'll be back with results soon. And remember, these are box stock SMALL BORE PRC 265's... I have half an urge to pull the heads and open them up another 10cc on both sides. This thing is way surpassing what I thought it was going to make on torque. I could be wrong but I think it was at 500ft lbs at 3k rpm.
07-15-2016, 07:26 AM
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At this point it's not a breathing issue, it's a valve float issue. I'll be back with results soon. And remember, these are box stock SMALL BORE PRC 265's... I have half an urge to pull the heads and open them up another 10cc on both sides. This thing is way surpassing what I thought it was going to make on torque. I could be wrong but I think it was at 500ft lbs at 3k rpm.
07-15-2016, 08:23 AM
#45
07-15-2016, 09:48 AM
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The only thing that makes these a "small bore" head is the valve spacing being closer together and the exhausts are 1.59, not 1.6. Same intake port.
Last edited by FRiCK; 07-15-2016 at 10:38 AM.
07-20-2016, 03:58 PM
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These are for a 4.065 0r 70 bore I believe. I had these for my 416 I was gonna build, then need up upping the bore from 4.070 to 4.135 with the ERL block.
The only thing that makes these a "small bore" head is the valve spacing being closer together and the exhausts are 1.59, not 1.6. Same intake port.
The only thing that makes these a "small bore" head is the valve spacing being closer together and the exhausts are 1.59, not 1.6. Same intake port.
09-26-2016, 03:06 PM
#49
Looking forward to seeing the results!
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Aaron @ Scoggin Dickey Parts Center
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Aaron @ Scoggin Dickey Parts Center
Email:Aaron387@sdparts.com
Phone: 1-800-456-0211 Ext: 324
12-14-2016, 06:37 PM
#50
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Well, after almost 6 months of back and forth, my engine builder relocating his shop and all the in between stuff. There was an issue with a wiring harness that was just noticed. Long story short, it was dyno'd today. Keep in mind this dyno session wasnt necessarily done for accurate numbers but more so to make sure the motor was good to go and to break it in.
It was dyno'd with a GMPP LS7 carb manifold, Holley 850 carb and 1 3/4" hooker headers.
Peaks were:
681.6hp @ 6800
600.2tq @ 5100
I hold the opinion that with my MSD manifold, NW 102 and my Kooks 1 7/8", power would have been higher.
It was dyno'd with a GMPP LS7 carb manifold, Holley 850 carb and 1 3/4" hooker headers.
Peaks were:
681.6hp @ 6800
600.2tq @ 5100
I hold the opinion that with my MSD manifold, NW 102 and my Kooks 1 7/8", power would have been higher.
12-17-2016, 05:41 PM
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I agree MAMOFIED MSD & 102 TB along with 1 7/8" LTs on that Dyno would have done 20-30 FWHP more.
What are your cam specs again?
What are your cam specs again?
Last edited by NAVYBLUE210; 12-17-2016 at 07:04 PM.
12-17-2016, 07:11 PM
#56
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That's correct. Waiting on some emails. But ide glady give up some of this tq for some more up top. I'm wanting it to peak about the same, maybe 6900 and pull clean to 7200. I think these 265cc ports keep velocity up, obviously. I was thinking about porting on them, but I think I'll keep them at 265, with the velocity increase over other heads that are 280+ I feel like it'll make whatever cam it's got, drive nicer.
12-17-2016, 07:22 PM
#57
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I absolutely think using the small bore LS7 heads on the full bore is an excellent idea, and I certainly wouldn't have them opened up unless you know for sure they are hindering progress in some way. I am a firm believer in coefficient of discharge, and using smallbore heads on an larger bore usually helps increase CoD. You get the benefits of the LS7 raised ports, as well as better intake port velocity due to smaller volume runners. I personally think the heads being 265cc smallbore LS7 heads makes them an extremely nice match for this build.
12-17-2016, 10:27 PM
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Wouldn't suggest an 8* split for your heads. I would ask Kip about
A 12* split something like 243/255 114+3. He nailed mine with a
6* split and I Dynoed with the same 1 3/4" Tri Y Dyno headers one day
Before you. I understand the exhaust to intake flow relationship and
The Texas speed stage 3 & 4 cams for LS7 heads have 8*
Exhaust splits for what that's worth. Still pretty good results
For your combo I would bet pretty close to 600 at the wheels
Dyno Jet with Tony's porting on your MSD with other mods
Mentioned and 3" exhaust.
Just my.02
Good Luck.
A 12* split something like 243/255 114+3. He nailed mine with a
6* split and I Dynoed with the same 1 3/4" Tri Y Dyno headers one day
Before you. I understand the exhaust to intake flow relationship and
The Texas speed stage 3 & 4 cams for LS7 heads have 8*
Exhaust splits for what that's worth. Still pretty good results
For your combo I would bet pretty close to 600 at the wheels
Dyno Jet with Tony's porting on your MSD with other mods
Mentioned and 3" exhaust.
Just my.02
Good Luck.
12-17-2016, 10:48 PM
#60
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Wouldn't suggest an 8* split for your heads. I would ask Kip about
A 12* split something like 243/255 114+3. He nailed mine with a
6* split and I Dynoed with the same 1 3/4" Tri Y Dyno headers one day
Before you. I understand the exhaust to intake flow relationship and
The Texas speed stage 3 & 4 cams for LS7 heads have 8*
Exhaust splits for what that's worth. Still pretty good results
For your combo I would bet pretty close to 600 at the wheels
Dyno Jet with Tony's porting on your MSD with other mods
Mentioned and 3" exhaust.
Just my.02
Good Luck.
A 12* split something like 243/255 114+3. He nailed mine with a
6* split and I Dynoed with the same 1 3/4" Tri Y Dyno headers one day
Before you. I understand the exhaust to intake flow relationship and
The Texas speed stage 3 & 4 cams for LS7 heads have 8*
Exhaust splits for what that's worth. Still pretty good results
For your combo I would bet pretty close to 600 at the wheels
Dyno Jet with Tony's porting on your MSD with other mods
Mentioned and 3" exhaust.
Just my.02
Good Luck.