Small Block Heads
#86238
07/09/08 09:57 AM
07/09/08 09:57 AM
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Joined: Nov 2006
Posts: 1,074
Manitoba Canada
67autocross
OP
super stock
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OP
super stock
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Manitoba Canada
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I'm building a 408" stroker small block out of a 76 360 block. I have the factory heads and could have them rebuilt but I don't want to put any money into porting old heads.
I was looking at mopar performance and they have these A engine heads on their web site. Has any one used these? Do you they oil through the push rods or can I just bolt them on the block and use the factory oil system? The part number is MOPP5007950. Thanks
Also what do you think would be a good cam for this combo? (9 to 1 comp)It will be a daily driver and want it to run like a stocker just with a lot more grunt.
From the add
A" Engine Replacement Cylinder Head — 2.02" Intake, 1.625" Exhaust
Based on the Magnum R/T big-valve head design and machined to fit 318/340/360 Mopar Small Block Intake Manifolds made through 1991. Imagine the new combinations
A new iron curtain drawn across the 49th parallel
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Re: Small Block Heads
[Re: 67autocross]
#86239
07/09/08 10:30 AM
07/09/08 10:30 AM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
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I think those are just mag r/t heads with LA intake bolt pattern. They are PR oiling. They are very good heads but way overpriced.
I have some iron heads that are just as good or even better in stock form if your interested. They are the pro-topline austrailian made heads. Mine are complete and cheaper complete than the R/Ts are bare. I also have some mopar aluminum magnums that are complete and will cost about as much as a complete set of R/Ts.
Another option is the EQ heads, no I don't have any of them but they are real good and very reasonable priced iron heads, almost as good as an R/T. They are all over E-bay called iron rams or heavy duty magnums.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Small Block Heads
[Re: dogdays]
#86241
07/09/08 02:47 PM
07/09/08 02:47 PM
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Joined: Nov 2006
Posts: 1,074
Manitoba Canada
67autocross
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OP
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Manitoba Canada
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What size chambers do the heads have? I'm looking to keep it in the 9 to 1 range as this is going in a car that I want to run mid grade pump gas.
A new iron curtain drawn across the 49th parallel
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Re: Small Block Heads
[Re: dogdays]
#86242
07/09/08 02:49 PM
07/09/08 02:49 PM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
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Very thinly veiled huh  I was just mostly trying to alert him to some better choices weather he buys some from me or someone else. I think the R/Ts and LA replacements are way overpriced for an iron head. You can get complete EQs off e-bay with 2.02 valves and decent springs for less than the R/T is bare on clearance at mancini, the place with the best deal. OOTB there is going to be little performance differance between the R/T EQ and Pro-Topline. R/Ts have better ports but tend to be very rough castings. The toplines have good ports and castings OOTB but slightly less maxed out potential then the R/T, the EQ is right below the PT but the 3 heads are very similar and any of them can make 600 with full porting. I only have one pair of the pro-toplines and two pairs of the mopar aluminum mags, keeping one pair for myself and selling the others. 
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Small Block Heads
[Re: 67autocross]
#86244
07/10/08 09:10 AM
07/10/08 09:10 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
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all the iron magnum heads are in the 63-65cc range. 10:1 with pump gas is doable with tight quench. for a cam, are you looking at flat tappet or solid? flat tappet, if you want to stay below .525" of lift with the 1.6 rockers, I'd actually look at the MP .484" lift cam (ends up being .512 with the mag rockers) with the 114 LSA, installing it at 106-108 ICL.
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
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Re: Small Block Heads
[Re: patrick]
#86245
07/10/08 09:31 AM
07/10/08 09:31 AM
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Joined: Apr 2007
Posts: 2,826
NY usa
540challenger
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master
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NY usa
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Quote:
all the iron magnum heads are in the 63-65cc range. 10:1 with pump gas is doable with tight quench. for a cam, are you looking at flat tappet or solid? flat tappet, if you want to stay below .525" of lift with the 1.6 rockers, I'd actually look at the MP .484" lift cam (ends up being .512 with the mag rockers) with the 114 LSA, installing it at 106-108 ICL.
Becareful with the lifts is that range makes sure you check retainer to guide clearance. I don't know about the mag RT or topline but if they are close to the stock Magnums It will be close.
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Re: Small Block Heads
[Re: 540challenger]
#86246
07/10/08 10:15 AM
07/10/08 10:15 AM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
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Even the stock magnum can make 400 hp with ease. The only ones to avoid would be the chinese made replacement heads, they are lousy quality. They are the real cheap ones on e-bay and do not have 318 cast onto the runners. You need to call and ask the company if they are the EQ because some of them show a pic of the EQ but are actually selling the chinese version, the company that does that is the one who told me about the chinese junk. I am not trying to make this political, the chinese are humans and deserve to be able to make and sell stuff, just this particular product is junk.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Small Block Heads
[Re: HotRodDave]
#86247
07/10/08 05:50 PM
07/10/08 05:50 PM
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Joined: Nov 2006
Posts: 1,074
Manitoba Canada
67autocross
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I don't want it to have 10 to 1 comp, I would like to keep it in the 9 to 1 range so I might just build the engine with the same 76 smog heads that came with it, I think they have around 68cc chambers which should work out to around 9 to 1 with flat top pistons, but how much power would I be giving up over magnum heads?
A new iron curtain drawn across the 49th parallel
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Re: Small Block Heads
[Re: 67autocross]
#86248
07/10/08 06:21 PM
07/10/08 06:21 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
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72cc more than likely.
Get out the old calculator, if you want a compression ratio of r, you divide the single cylinder swept volume by (r-1) to get the volume above the piston.
So a 408 is 51 cubic inches per cylinder, meaning 836 cc. 836 / (9-1) = 104.5 cc above the piston. That means you need 32.5 cc in dish, head gasket volume and volume above the piston by way of piston being down in the hole. So take out 5 cc for the valve notches and you have 27.5 cc to find. That means the piston has to be, together with the head gasket, 0.131" below the head surface if the piston is a flattop with the aforementioned 5cc valve notches.
So if you have a 408 with a 0.039" gasket, say 10cc, with a zero deck flat top piston with 5cc valve relief and a 63cc Magnum chamber you will have 78cc above the piston making (839 + 78)/ 78 = 11.76:1! Doggone, those strokers make higher compression ratios quick!
R.
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Re: Small Block Heads
[Re: 67autocross]
#86249
07/11/08 12:10 AM
07/11/08 12:10 AM
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Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
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If you use iron magnum heads and set it up to get a tight quench and a normal sized mild performance cam, 10 to one compresion can run on 87 octane. With aluminum magnums and tight quench you can run 11 to one on 87. I run 10 to one compression and a stock 2bbl cam and I can get away with 91 octane. Any decent performance cam will alow you to run 87 because it bleeds off cylinder preasure. Also if you are willing to run premium fuel you can bump the compression even more and that will help MPG enough to offset the cost, that is why I built my engine the way I did.
Another thing about the "smog" heads is they have really bad combustion chamber desighn, the magnum has one of the best the differance in chamber desighn can make up to a point in compression tolerance, meaning a 10 to one magnum will be no more likely to knock than a 9 to one "smog" head.
There have been several tests between the best smog head, the 308, and the magnum and with the same motor the magnum head consistantly makes about 25 hp more with no other changes.
Don't be afraid to run 10 to one with a magnum style head.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Small Block Heads
[Re: HotRodDave]
#86250
07/11/08 08:27 AM
07/11/08 08:27 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
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use the 20cc dish diamonds with mag heads and tight quench (yields ~10:1) and a moderate cam (say, 230@.050) and you should be able to easily run on 89 octane. a little larger cam (say, 240-250@.050) and 87 octane should be doable. of you're still concerned about detonation, take some sandpaper rolls and a die grinder and polish the combustion chambers, and put a slight round on the sharp edges on the top of the pistons. that'll help eliminate hot spots, and add a CC or 2 to the chamber volume.
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: Small Block Heads
[Re: dgc333]
#86252
07/11/08 11:07 AM
07/11/08 11:07 AM
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Joined: Jan 2003
Posts: 16,376
dogdays
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Thanks for the testimonial. What cam are you running in your 10.6:1 motor?
With all the advantages of higher compression ratios I can see no reason to lower the compression ratio if one can run the engine on readily available gasoline.
R.
PS: The mag head does have a superior chamber, the LA open chamber was basically wrong.
Last edited by dogdays; 07/11/08 11:08 AM.
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