EQ 408 Build - Head Gaskets
#2452559
02/16/18 02:32 PM
02/16/18 02:32 PM
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Joined: Mar 2005
Posts: 403 Colorado front range
BcudaChris
OP
mopar
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OP
mopar
Joined: Mar 2005
Posts: 403
Colorado front range
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Moparts Brain Trust,
I'm building a Magnum based 408 for my 73 Barracuda,using EQ heads (Hughes prepped). Compression will be right around 10.25:1, forged pistons, Hughes 3034 cam. Primarily a street engine, but Power Tour is on the calendar and I'll be sorting the car out at the drag strip and on a local circuit. I am compromising almost everywhere in favor of durability over power output.
Question on head gaskets. FelPro 1008 or Cometic CGT-C5916-036?
I've always had success with FelPro, and never used Cometic. But the cometic option is listed specifically for the EQ heads. It also has a 4.04 bore as opposed to 4.108 bore, and .036 compressed thickness instead of .039". Final finish bore is at 4.020"
Can anyone offer a compelling reason to spend 2x the cash on the Cometics? They are ostensibly designed/optimized for use with the EQ heads.
My assumption is that the top layer finish of the gasket is optimized for the modern cast iron and finish machining of the EQ heads.
I should add that this is my first build in a decade, and first ever doing anything but the getting the best power I could out of factory hardware, on a budget. My last setup was a 333ci 318 based, Erson hyd mid-range flat tappet and 302 heads with big valves and a fancy valve job, LD4B and an AFB. It peaked at ~240HP @ 5200 and 290ftlbs @4600 on a chassis dyno at 5280'.
Any advice appreciated.
Thanks Chris
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Re: EQ 408 Build - Head Gaskets
[Re: BcudaChris]
#2452706
02/16/18 06:56 PM
02/16/18 06:56 PM
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Joined: Jan 2010
Posts: 1,442 NW Chicago suburban area
Mopar Mitch
pro stock
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pro stock
Joined: Jan 2010
Posts: 1,442
NW Chicago suburban area
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Chris -- I'm a former Fel-Pro aftermarket engineer and was involved with the development of the 1008s, etc... my 340 engine was a test engine... lasted past 30+ years with the 1008s.. came off clean.. held 10.5 CR a-ok. The 1008s (as the balance of the wire-ring design FP race gaskets) are a high CR sealing design, typical from diesel designs that seal easily over 16-18-20+ CR. (and far superior to the standard 8553 FP passenger car head gaskets, for CR sealing and resistance to detonation/pre-ignition = burnout). The fiber-facing seals fluids much better than a metal-faced design (the metal faced design, such as the MLS gaskets in the marketplace, requires ultra-smooth surface finishes -- most machine shops cannot provide, or don't spend the time, to make that ultra-smooth surface finish).
For our old iron engines, even with optional aluminum heads, you can feel confident that the 1008s are excellent. The MLS gaskets are over-kill for most applications, pending the engine design. Save your $$ and use the 1008s... they are the only head gaskets I'd ever use on my SB mopar (likewise the 1009s for the BB).
Mopar Mitch
"Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers!
Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
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Re: EQ 408 Build - Head Gaskets
[Re: BcudaChris]
#2453848
02/19/18 12:02 PM
02/19/18 12:02 PM
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Joined: Nov 2004
Posts: 3,544 Syracuse,NY
CompWedgeEngines
master
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master
Joined: Nov 2004
Posts: 3,544
Syracuse,NY
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Remember, the Magnum head is just a " touch" different than the old LA, but directly from EQ:
The production Magnum head gasket is a unique design, however the changes from the LA series are primarily to corral the pushrods into position during assembly. Regular LA engine gaskets can be used here.
RIP Monte Smith
Your work is a reflection of yourself, autograph it with quality.
WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.
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