What cam to use in a 318

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furz4 said:
By the specs I bet that would be a good runner probably too much lift for my 1.6 rockers without cutting the guides down.
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I've seen stock guides interfere with retainers at .450 lift, so cutting guides down should be a part of your build regardless. You have to run the matching springs with whatever cam you choose anyway, so the springs have to come off regardless.
 
70coupe said:
If you say so.

It works great for me but just like OP I am not a bracket racer or a number chaser. Make of that what you wish.
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Sir, I don't mean to sound disrespectful but read what I said and you'll see that I was asking if it's to much cam for the 318 that's being discussed that has a 9.2:1 CR. I didn't mean or say that it's too much cam.
 
I have the Hughes springs and retainers on the magnum heads with .510 lift the seals just clear so I wanted to stay a little less then that, that's why I was thinking around .500 max . My current 318 runs a factory 340 automatic cam which is 210 & 220 @.050 runs good but I doubt the compression is even 8:1 and lift is only .421 .444 I believe. I had thought of running that in this motor with the 1.6 rockers but I think there are better choices then 114 center line, I think 110 would probably work better. Something like the comp 20-417-3 perhaps, although I am not sure a dual pattern cam will make much difference on a street car but they are widely used when running full exhaust.
 
I wouldn't run Comp cam or lifters for love nor money.
 
Well I am not a big comp fan either I have heard of lots of problems with them, although to be fair it's probably the lifters that cause most problems these days. A lot of this stuff is just not made of good material and is not sufficiently hardened. I have though about going roller but the cost just seems pretty crazy given the inflate price or components these days
 
furz4 said:
Well I am not a big comp fan either I have heard of lots of problems with them, although to be fair it's probably the lifters that cause most problems these days. A lot of this stuff is just not made of good material and is not sufficiently hardened. I have though about going roller but the cost just seems pretty crazy given the inflate price or components these days
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There was a member very recently who said they spoke with Comp and whoever it was they spoke with actually admitted they are using inferior metal.
 
Does any camshaft company offer a exact reproduction 340 cam? I've found a few that the advertised duration is correct but the duration at 0.050 is more, the lift is never correct either. The 340's were discontinued 51 years ago and I don't know if the patent rights are still in effect.
 
Furz4,
You have given this considerable thought....& your reasoning is excellent. The only incompatibility I see is 3.23 gears & a high stall c'ter. Not a big deal, but something to think about in the overall picture.
Refreshing also to see somebody thinking about the cam & not automatically installing Big Bertha.
I would use the Isky 270 Mega cam. I have used a lot of the Mega cams. The tight 108 LSA is going to give you more HP.
221 @ 050 might not sound that big, but it has 12* more overlap than the same grind on 114*. Single pattern, lift will be 0.496" with 1.6 rockers.

Remember, easy to go too big. Have factory lifters re-faced if you do NOT want lobe/lifter failure, no matter what brand the cam/lifters are.
 
Curious how the OP got to 9.2:1 in a 1973 engine.

Did the Magnum heads do that?
Were they shaved?
Different pistons?

Most of the sources I found a few years ago said .520 for max lift on Magnum heads.
 
furz4 said:
I have the Hughes springs and retainers on the magnum heads with .510 lift the seals just clear so I wanted to stay a little less then that, that's why I was thinking around .500 max . My current 318 runs a factory 340 automatic cam which is 210 & 220 @.050 runs good but I doubt the compression is even 8:1 and lift is only .421 .444 I believe. I had thought of running that in this motor with the 1.6 rockers but I think there are better choices then 114 center line, I think 110 would probably work better. Something like the comp 20-417-3 perhaps, although I am not sure a dual pattern cam will make much difference on a street car but they are widely used when running full exhaust.
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The extra exhaust duration helps get more exhaust gases out and will add a few more rpm to a single patterned camshaft. Headers or not.


Garrett Ellison said:
I like this cam for that combinbation. 108 LSA & 104 ICL DODGE Howards Cams 710991-08 Howards Cams Hydraulic Flat Tappet Camshafts | Summit Racing
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I running this one in my 5.9 with the trick Hughes springs and retainers.
(727/2500 stall, 3.55 gears.)


IMG_0982.jpeg

Dan the man said:
Does any camshaft company offer a exact reproduction 340 cam? I've found a few that the advertised duration is correct but the duration at 0.050 is more, the lift is never correct either. The 340's were discontinued 51 years ago and I don't know if the patent rights are still in effect.
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Mellings makes OEM repops.
Patents expire after a few years. There is a discussion on in the W5 copy thread. There is also a link in there on patents.
 
rumblefish360 said:
What kind of lift do the Magnum’s handle stock?
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I’ve seen em hit at .470 true valve lift, and seen some ok at .512 true lift. Because of the horrible pushrod angle, you have to measure at the valve and not just go by the lift on the cam card. As with anything engine building, the correct answer is, you have to measure.
 
furz4 said:
I have the Hughes springs and retainers on the magnum heads with .510 lift the seals just clear so I wanted to stay a little less then that, that's why I was thinking around .500 max . My current 318 runs a factory 340 automatic cam which is 210 & 220 @.050 runs good but I doubt the compression is even 8:1 and lift is only .421 .444 I believe. I had thought of running that in this motor with the 1.6 rockers but I think there are better choices then 114 center line, I think 110 would probably work better. Something like the comp 20-417-3 perhaps, although I am not sure a dual pattern cam will make much difference on a street car but they are widely used when running full exhaust.
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I wouldn't say you got lucky that you had clearance, but it varies so much, you never know till you put it together.
 
^^^
TT5.9mag said:
I’ve seen em hit at .470 true valve lift, and seen some ok at .512 true lift. Because of the horrible pushrod angle, you have to measure at the valve and not just go by the lift on the cam card. As with anything engine building, the correct answer is, you have to measure.
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^^^ This Right Here^^^ And sometimes in places you don’t even expect, like the pushrod holes.
 
It’s just breaking in! Well, maybe just breaking…
 
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