Eddy heads 340 vs 360

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4spdragtop

4spdragtop

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Hi all, can anyone tell me what and if there is a difference in Eddy heads #6077?
I fired up the Google machine on the 6077's and found an old thread on Moparchat where it mentioned a difference due to the 340 pistons sticking out of the deck?
Also are there issues using stock accessories, power steering, alternator?
Thanks
Steve
 
Steve, the 60179 Edelbrock 340 heads have a 0.060" inch relief cut for the above deck pistons. 65'
 
The version designed for the 10.5 compression 340 engines have more material removed from the combustion chamber so the pistons which protrude from the block will not contact the deck surface.

Putting this version Eddy’s on a zero deck piston will produce less compression than the other version of the Eddy’s given their larger combustion chamber cc’s.
 
The heads I'm contemplating are 6077 to use on my 340, which the pistons protrude "slightly " above deck.
 
4spdragtop said:
The heads I'm contemplating are 6077 to use on my 340, which the pistons protrude "slightly " above deck.
Click to expand...
One set, 360 app are a typical closed chamber..While the 340 app head opened .060 deep on the closed side.
The 340 pistons can stick out of the block around .019-.024 if you figure in squaring the block...but always measure and see what you got. Figure the head gasket compressed thickness... some are .052-.054 thick... ex. so take .024 from that and you have .030 quench with the 360 part number head. Thing to consider is .060 relief is overkill. The piston the gasket plus the chamber relief -.024 adds to around .080 depending on which head gasket. lol
You can run .030 and be fine...so you could use a 521sd/519sd gasket at .054 compressed and run the std closed 360 app version and have that .030
Or you can use the other, but that's. 060+.039 '1008' -.024=.075 gigantic and useless.
They say the compression may too high as well, why they do that.. but are you running the stock cam like they account for? That's the diff.
 
Sometime alternator issues can arise with aluminum heads because they are flat on the alternator mounting face and not recessed like stock heads.

How much is slightly? The .060 cut is way to much if the protrusion is at the spec approx +.019.
 
A set of .060 to .070 compressed thickness Cometics will usually take care of most above deck 340 pistons with closed chamber aluminum heads. Like mentioned, measure beforehand and then select gaskets based on piston to head/squish/quench clearance (some people say that when it's right it's actually a tumble in the chamber, that the mixture is rolling through the across the chamber at the spark plug). That alternator clearance deal can be a real issue, even with aftermarket pulleys and their spacer selection. The less accessories you run the easier it is to overcome. A factory location AC compressor is a real pain to configure with aluminum heads.
 
Factory 71 specs per NHRA are around .45 Above Deck with 028 gasket
and that is exactly where we run then with alum heads.
 
Thanks guys, the pistons sit outta the hole approx .034". That's me doing a redneck measurement with dial indicator, so +/- lol.
Head gaskets are Felpro 1008, I believe are .043 compressed.
I have x heads, sounds like it might not be worth the effort (to me anyway) when taking into account possible alternator issues etc.
Thanks all
MOPAROFFICIAL said:
One set, 360 app are a typical closed chamber..While the 340 app head opened .060 deep on the closed side.
The 340 pistons can stick out of the block around .019-.024 if you figure in squaring the block...but always measure and see what you got. Figure the head gasket compressed thickness... some are .052-.054 thick... ex. so take .024 from that and you have .030 quench with the 360 part number head. Thing to consider is .060 relief is overkill. The piston the gasket plus the chamber relief -.024 adds to around .080 depending on which head gasket. lol
You can run .030 and be fine...so you could use a 521sd/519sd gasket at .054 compressed and run the std closed 360 app version and have that .030
Or you can use the other, but that's. 060+.039 '1008' -.024=.075 gigantic and useless.
They say the compression may too high as well, why they do that.. but are you running the stock cam like they account for? That's the diff.
Click to expand...

dano said:
Sometime alternator issues can arise with aluminum heads because they are flat on the alternator mounting face and not recessed like stock heads.

How much is slightly? The .060 cut is way to much if the protrusion is at the spec approx +.019.
Click to expand...

Garrett Ellison said:
A set of .060 to .070 compressed thickness Cometics will usually take care of most above deck 340 pistons with closed chamber aluminum heads. Like mentioned, measure beforehand and then select gaskets based on piston to head/squish/quench clearance (some people say that when it's right it's actually a tumble in the chamber, that the mixture is rolling through the across the chamber at the spark plug). That alternator clearance deal can be a real issue, even with aftermarket pulleys and their spacer selection. The less accessories you run the easier it is to overcome. A factory location AC compressor is a real pain to configure with aluminum heads.
Click to expand...

GTX JOHN said:
Factory 71 specs per NHRA are around .45 Above Deck with 028 gasket
and that is exactly where we run then with alum heads.
Click to expand...

20180118_211637.jpg
 
I have been mocking up a 340 I am putting together, the TRW forged replacement piston is. 013 above the deck. So I ordered the Cometic .027 head gaskets for the X heads I am using
 
X heads have a deep chamber unless they've been milled wafer thin. Sometimes you can find NOS steel shim Mopar replacement head gaskets on eBay.
 
There’s plenty of room for steel shim head gaskets with X heads. The last pair I measured had been cleaned up (probably .007) and still averaged over .080 deep on the shallow side of the chamber. They measured 72ccs with stock tulip style valves. A .020 cut would put you around .044 piston to head with the I believe .018 thickness if your heads are close to that (.060+.018=.078-.034=.044). The greater problem I’ve seen with ChryCo iron heads is there’s usually 1 end chamber that’s cast at less than half of the depth of the other chambers. I’ve got a five inch base depth mic that is great for showing the inconsistencies in the chambers of a regular production head. .020 depth variance is about the best I’ve come across so far.
 
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If it was me;
and I was going alloy
I would buy the 360 closed chamber heads, use the .039 FelPros, and machine the tops of the pistons off to set the Q to whatever I wanted. You can't really get too much compression ratio, doing it this way. And as I have said many many many times I run 87E10 at up to 185psi cylinder pressure, with full-timing.
My Q is set to in the range of .032 to .034.
At zero-deck,your 340 will fall together at about 10.2 Scr, and with a factory 340 cam the Ica is about 66*, so the Wallace says your pressure will be about 160psi. So IMO, you can do better than that cam, and pop your pistons out of the holes a little as well.
With the pistons up to .007, and assuming a total chamber volume of 74.8, your Scr at 4.04 x 3.315 comes to 10.31 .. A 268/276/110 cam would get you an Ica around 62, and at 400ft Elevation, the Wallace spits out a pressure of just 170 so you too cam burn 87E10; with plenty of head room.
As for me, I might be inclined to leave the dome alone in the open part of the chamber and shoot for 180 pressure
I'm just doing some preliminary math here, not telling you what to do ...............
cuz at 160psi you can run iron heads with tight-Q, but to get the tight-Q will be a challenge as already detailed; it's just more machining, more things to go wrong, and still gonna cost a bundle. and in the end, you still got an X-head to deal with.

as for the alternator, my squareback was no problem to make fit.
 
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