EQ heads on LA 318 question

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Jonnylightening

Jonnylightening

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Ok guys i bit the bullet and bought the EQ heads. My uncle has factory magnum heads on a junk yard engine (cracked block) so he said i can take whatever i needed from the heads. Before i desided to do the EQ head swap i bought a Summit cam/lifter kit along with mating springs. Questions i have are:
*what pushrods will i need (length)
*will my LA valve springs work
*can i use the stock magnum valves if they are in good condition
*will the LA valve seals work
If im missing anything please let me know im tryin to get an idea of what alls needed to bolt EQs to my LA
 
Jonnylightening said:
Ok guys i bit the bullet and bought the EQ heads. My uncle has factory magnum heads on a junk yard engine (cracked block) so he said i can take whatever i needed from the heads. Before i desided to do the EQ head swap i bought a Summit cam/lifter kit along with mating springs. Questions i have are:
*what pushrods will i need (length)
*will my LA valve springs work
*can i use the stock magnum valves if they are in good condition
*will the LA valve seals work
If im missing anything please let me know im tryin to get an idea of what alls needed to bolt EQs to my LA
Click to expand...
Chrysler Magnum | A&A Midwest
There are a lot of articles out there that cover your questions, I don't want to guess so here's one. I'm doing magnum heads on a 340 sometime down the line, good luck.
 
Jonnylightening said:
Ok guys i bit the bullet and bought the EQ heads. My uncle has factory magnum heads on a junk yard engine (cracked block) so he said i can take whatever i needed from the heads. Before i desided to do the EQ head swap i bought a Summit cam/lifter kit along with mating springs. Questions i have are:
*what pushrods will i need (length)
*will my LA valve springs work
*can i use the stock magnum valves if they are in good condition
*will the LA valve seals work
If im missing anything please let me know im tryin to get an idea of what alls needed to bolt EQs to my LA
Click to expand...
Ok , I can help but need more info.

What are springs specs?
What size is cam?
My guess is most wont work as most LA heads are 3/8 valves and Mag's are 8mm. Seals wont work. If block in mag is cracked, so you really want to reuse valves?
Probably want new valves, springs, retainers, seals and locks. You will need new head bolts too.
We have:
head bolts for $35
cromo push rods $99
fully polished stainless valves $125
factory replacement valves $88
viton valve stem seals $15
Factory replacment spring/ret/lock kits $80
Stage II spring/ret/lock kits $150 but out of retainers for a few.
find us on web at magnummopar. or pm for shop phone.
We can sharpen our pencil a bit but these items are already seriously discounted. Evan magnummopar.
 
Valve Springs:

Outside Diameter 1.394 in.
Inside Diameter 1.020 in.

Cam Specs:

Hydraulic Flat Tappet, Advertised Duration 272/272, Lift .454/.454
 
If the magnum valves are in good shape and you decide to use them make sure and have a professional check the guide clearance because some heads use 5/16" valve stems and others use 8mm valve stems and there's only .002" difference between them. If you use the wrong ones you could either have real sloppy or way too tight guides. My head guy has a valve guide mic for checking clearance. Nothing more accurate than that
 
Jonnylightening said:
Seat pressure 90 lbs

Installed height 1.650"

Open pressure 178 lbs. @ .375"
Click to expand...

There are three issue's using the OE springs.
1. They are barely capable for the stock cam.
2. Magnums have a bit of a rep for having sticky guides.
3. They coil bind at just over .500 lift.

Even if you just stuck with the stockish cam, the spring kit would be highly recommended for the 310 lbs open pressures.
They are a lot more likely to make sure the valves close before the piston gets there and lessen the sticky guide possibilities being an issue.
 
Assuming you are going to keep the 272 .454 cam, I'd get better springs. Off the magnum I'd take the whole thing. Off the heads you should be able to use the rockers, intake valves (have the stems measured and grind faces), maybe retainers, check exhaust valves very close for wear surface finish and good faces, valve covers, head bolts. From the block use or stockpile the cam, lifters (spiders and all), crank, damper, rods and pistons, and all the bolts and hardware.
 
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Going off "318willrun" thread i bought the same cam and springs he did. So i need to exchange my current springs for? Before i purchased my heads i was planning on doing a mildish 318 build with LA heads. Will the cam work or is it on the small side?
 
Jonnylightening said:
Going off "318willrun" thread i bought the same cam and springs he did. So i need to exchange my current springs for? Before i purchased my heads i was planning on doing a mildish 318 build with LA heads. Will the cam work or is it on the small side?
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Are the springs recommended by the cam manufacturer for the cam you bought? With EQ heads the cam should be fine, you could even go smaller. Are you going to use the EQ heads? There is something wrong with the spring specs. Did you mean 178 lb @ 1.375 in? I would also check the installed height as 1.65 seems short to me. I'm more familiar with LA than Magnum, but LA spring heights usually measure about 1.69. At 1.65 -.454 leaves a 1.196 open height. If it is 90 @ 1.65, and 178 @ 1.375, that makes the springs 320 lb/in, that means at 1.196 you are getting 235 lb at open and that is more like it. 178 lb @ open is not good enough.
 
Jonnylightening said:
There Edelbrock #5877 springs. Thats what the specs are on the site
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Wow you are right. Assuming their numbers are correct, a 235 lb/in spring rate. The bad part is coil bind is at 1.203 inches. If your installed height is 1.65-.454 = 1.196. Can you say broken or bent parts? If your installed height is 1.69 then coil bind is at 1.236, just .033 clearance. Your closed load is now 80.6 lb and your open load is 187.3 lb. If your installed height is 1.72 in you have .063 clearance from coil bind. Closed load is 73.6 lb while the open load is 180 lb. Definitely marginal for a .454 lift cam and definitely bad if set at 1.65 installed height. For reference a 340 spring has a spring rate of 386 lb/in and @ 1.69 closed load is 69 lb and open load is 244 lb.
 
In your opinion what springs do you recommend for that cam? Seems as though you know just alittle about valvetrain hahaha!!
 
Jonnylightening said:
In your opinion what springs do you recommend for that cam? Seems as though you know just alittle about valvetrain hahaha!!
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Actually my calculations were off. Magnums use a 1.6 Rocker ratio, so your lift is theoretically .484. So, I'd start looking at Magnum springs rated to .50 inch of lift. Yours will not work. 340 springs will not fit into a magnum seat as they have too large an OD. The best thing to do is to take your measurements, Installed Height, and go from there. There are a few Vendors here that could give a better recommendation since they sell EQ heads.
 
Stock magnum springs are 85#@1.6 OD is 1.320". They coil bind at .480" so we dont recommend more than about .460" lift. Our stage II springs are 120#@1.660 and will handle .550+" lift OD 1.420" which is probably larger than the 340's but I dont have any 340's to measure here.
OP, did the place you got heads from offer you any advise on all these parts?
I would also not recommend reusing old valves as you can damage new guides installing old valves and most of the heads we take apart have worn valve stems. You can reuse the rockers if they are good. Head bolts are supposed to be changed out each time but nobody does. To me, its not worth $35 to clean old ones up.
 
Bought the heads from jegs. I was gunna use mainly the retaineers and locks but want to get new springs and valves
 
magnummopar said:
Stock magnum springs are 85#@1.6 OD is 1.320". They coil bind at .480" so we dont recommend more than about .460" lift. Our stage II springs are 120#@1.660 and will handle .550+" lift OD 1.420" which is probably larger than the 340's but I dont have any 340's to measure here.
OP, did the place you got heads from offer you any advise on all these parts?
I would also not recommend reusing old valves as you can damage new guides installing old valves and most of the heads we take apart have worn valve stems. You can reuse the rockers if they are good. Head bolts are supposed to be changed out each time but nobody does. To me, its not worth $35 to clean old ones up.
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Stage II sound good. Definitely still check installed height. 340 OD is 1.50+ from memory. Checked OEM Magnum seat diameter was too small.
 
OP, arent the LA stems 3/8"? If so, retainers and locks will not fit 8mm valve stems. If you are talking about the stuff off mag heads, retainers and locks are dirt cheap.
 
Tryin to build my current engine as cheap as possible. Later on i want to build a turbo motor so as long as i can save and get alittle more out of this one that works for me. If i can just buy springs, valves, and pushrods i think ill be set
 
What MagnumMopar said about the springs binding and having a short installed height is solved by the spring kit made for using o EQ heads to allow up to approx. .600 lift with 310 open pressure.
The retainers are made with more clearance under them.
I used those with a 512 lift cam and still had plenty of room.
Also mentioned already is that EQ Magnum heads use an 8mm valve stem and OE LA engines use a 3/8 stem.
The difference is only a couple of thousands, bet plenty to give real sloppy clearances.
The custom Magnum springs are made for the 8mm stem valves.

Hope this helped instead of making it more confusing.
 
Jonnylightening said:
Tryin to build my current engine as cheap as possible. Later on i want to build a turbo motor so as long as i can save and get alittle more out of this one that works for me. If i can just buy springs, valves, and pushrods i think ill be set
Click to expand...
I have head bolts and rockers. I think they will fit n a medium flat-rate box about 25 bucks shipped if you need them!
 
If the stock valves have a lip on the back you will want to get them back cut.
 
What type EQs do have? LAs or mag rockers? LAs are 1.5s and mags are 1.6 this makes a difference on final lift which effects spring pressure which effects spring pressure requirements.
 
TrailBeast said:
What MagnumMopar said about the springs binding and having a short installed height is solved by the spring kit made for using o EQ heads to allow up to approx. .600 lift with 310 open pressure.
The retainers are made with more clearance under them.
I used those with a 512 lift cam and still had plenty of room.
Also mentioned already is that EQ Magnum heads use an 8mm valve stem and OE LA engines use a 3/8 stem.
The difference is only a couple of thousands, bet plenty to give real sloppy clearances.
The custom Magnum springs are made for the 8mm stem valves.

Hope this helped instead of making it more confusing.
Click to expand...
Its the springs that limit lift, the retainers will clear .600 but springs will bind at .575 and honestly, when you get past .550" you need stiffer springs and different lifters.
Its the retainers and locks that are made for 8mm or 3/8 stems, not springs. If you tried to use 3/8 retainers and locks on 8mm valve the valve would pull out of the retainer and lock when you took spring compressor off. Its 5/16's thats .0025" smaller than 8mm, 3/8's is .0625 larger.
 
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