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#1
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Port my EddyÂ’s or stroke it
IÂ’m getting ready to reassemble my 360, but IÂ’m not sure what would benefit my ETÂ’s the mostÂ….buy a crank and pistons to stroke it to a 408, or have my Edelbrock heads fully ported. Not enough money to do both.
The rest of the combo / parts: 360, Scat I beam rods (new) Comp solid roller, XR286R, 248/254 duration with .576/.582 lift (new) Air-gap intake, 750 dp 727, 8 inch PTC converter (new) 4:10 gears, 3250 lbs with driver in 67 Barracuda. IÂ’m leaning toward porting the headsÂ…but I just donÂ’t know. The car is 80-90% race with some weekend street use. Thanks in a |
#2
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Do the heads. At least if you later decide to do a stroker short block, you'll already have heads that will keep up with the extra cubes. Heads are key.
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#3
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Agreed....
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#4
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This is a good question, what do ya do?
I mean porting the heads will definitely increase the flow=HP/torque 25-40 each and would be great on a 360ci motor. And putting in a 4' stroke crank will definitely increase the HP/TQ as well with more emphases on the TQ to the tune of around 65+ or so ft lbs and would be pulling the soul out of those eddys as is, which I'm not sure how much material will be removed in the port job your describing but I wonder if it will be enough to get enough port volume to properly feed that stroker in the long run, Maybe do the stroker and later buy W2's would be the best bet ? I don't know this is a tough one.... |
#5
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I'd stroke it first. That way the hard parts over with. You can pull the heads without removing the whole engine at anytime. If you do the heads now, then want to stroke it you have to pull the whole thing back out and just about start all over again. Less work to stroke it now and rehead the thing later on.
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#6
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stroking will raise the compression up to where you need it with aluminum heads + that cam ?
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#7
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What is hte current state of your 360 short block? Which pistons etc? I agree with DWC43, first get the short block done, everything else is easily changed later without having to tear the whole thing down. If your current 360 short block is recelntly built with good quality parts, I would leave it as it is. If it needs rebuilding, definitely go with the big arm crank. You have a pretty serious cam in there, and might do better with a single plane wether you stick with 360 cu in or go with 4" stroke.
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#8
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Depends on the porter.....
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#9
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agree...stroke it! you will get alot of tq in the low rpm! but you will not reach a 408`s full potensial with eddys untuched!
the eddys hardly reach 300cfm ported with $$$$(correck me if wrong) and I believe 300 is the lower limit for an 90% race 408! it all comes down to the combo: engine,converter and rear + tiresize. if you stroke it and leave the eddys as is, you have an engine that stops pulling before 6k, but you have ALOT more power before the 6k limit if you port the heads you will have a 360 that can make power past 7k, but it will not pull as hard as the stroker in the lower rpm-s. |
#10
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Gonna drag race? Stroke it. The extra torque will move you off the line faster, faster 60 ft times, and put you out front sooner. If you port the heads first, you're gonna put your power up high, and have the engine pulling at the end of the race. Port the heads later, there's no substitute for cubic inches...
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#11
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I knew that would spur some thought.
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#12
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Theres also a RPM issue.
The cam isn't that big. Once in the stroker, which eats up cam duration a bit due to the increased size, the port volume of the head will only be good to a certain RPM because of it's size. And then the rest of the combo comes into play to limit it's abilties. Most strokers peak @ 6000 rpm and that cam isn't pushing any bounderies. |
#13
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If it were me, I would just port the heads, your other option sounds like a "new buildup" If its running and racing now, the porting will pick up some power, building a new engine will cost alot more. The stroker motor will make more power, but you still need to port your heads with the stroker, see what I am saying?
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#14
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Depending on the head porter....
I would build the short block with the stroker.... but if you have any other "assembled" heads then I would choose to run those... possibly some J or X heads sitting in the garage? Save up for the heads to be ported, and have a cam cut for your application and heads.... Once money and time permits, do a weekend install of the Eldy heads and new cam, very little down time with less work involved, and you bring your potential out in your motor... |
#15
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Hard to beat 'pubic inch'=torque, see what I mean.lol
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#16
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Quote:
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#17
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It's the port volume & int/exh ratio, not the flow that limits the rpm.
You bet it will take a lot of material removed to get the port volume correct for the cubes, thats why I said W2. You bet with more swept volume that he will be getting every bit of that 260cfm that the stock eddys have to offer. While you do need horse power you have to have torque first. Horsepower sells cars, torque wins races.JMO I guess I am the only one..... |
#18
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Quote:
But porting creates torque too.... but which one will produce more?.... depends on the porter |
#19
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...So put some stock heads on YOUR 408!lol jkn
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#20
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2.02\1.6 valves is too small for 4" stroke!the valve size vs time vill choke the engine at 5500rpm on a pretty good bumpstick. @.500 lift @ valve, and since there is no room for bigger valves,the only thing that can get more air in is lift! pipemax tell me to use .700+ lift to get the choke up to ~7000rpm... and 700 lift is a pretty wild roller! and in my world too much for the street!
check it out... 660hp , 260\268@050 roller.... guess this "little" baby scream http://www.popularhotrodding.com/eng...410/index.html |
#21
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Just take your current engine wiht the J-heads to a "magazine dyno" at Westech, and be happy. There is no way anyone would want to use much over 0.6" lift with the RPM heads, they have short valves and low spring installed heights and the SB mopar valvetrains pushrod angles really arenät best suited for extremely high lifts and rpms. We just recently built a 4" stroekr with rpm heads and rpm intake, the cam was a solid flat tappet, with close to the same lift that's in your street roller. It made 455 true hp at 5800 rpm with 1 5/8" headers and a 650 cfm carb. The heads were homeported, not really anyhting wild, and the engine had excellent low end torque, pulling very strong from 2000 & up and making 490 ft-lb peak at 3800
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#22
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Stroke it first.
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#23
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Quote:
Quote:
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#24
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Quote:
well, I`m only a younggun with little experience, so I will shut up but can I ask for your opinion about why most of the 408s peak before 6k? and about .700 wild...I talking about street-driving whitout tearing down the engine every sec winter... |
#25
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Why make a motor turn more RPM's than needed? I was just saying with the right heads, and cam, a 408 will have no problem revving to 6500-7000rpm... of course figuring you're bottom end has a good combination. RPM's kill motors, but also like you said higher lift cams can kill valvesprings.... unfortunately there's just so many different variances in these stroker builds, with different parts from all over.... it's hard to group them in a "general" 4" SBM can do this but can't do that category.
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#26
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Quote:
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#27
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Good answer TeamDart.
Quote:
You can cam the sucker to death, but, that doesn't give it an automatic ticket to 7500 rpm. All the rest of the parts need to be in sync and up to par. Valve lift. Is a funny thing. You can get a cm to lift this high with as many duration numbers as there are lift numbers in all the catologs you can find. Generally speaking, .700 lift would be considered a heck of alot for a street engine. Then again, it may not be a whole lot for a crazy full throttle strip car. The thing that wears out springs on a head is lift and the amount of abuse it sees. |
#28
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I thnk he was trying to say, use the iron heads for now while the edel.'s get ported.
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#29
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Yessum
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#30
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but WHY does longer stroke make the peak come earlier?
(my theory) it`s because the longer stroke make the piston travel further, and if the piston travel furter, you need to get more air in to fill it completely! and there is simply not enough room + time with a 2.02 valve to get in enough air with a decent street camshaft.it is the pumping part that does most to get air in to the cylinder. (picture) duration does little to widen the pumping area... but lift and valve size do! but I agree....we dont want more than 6.5k...speed kills! in my world it is better to have a strong engine up to 6500, and then stop it with a rev-limiter rather than use a choked engine as the rev-limiter... (sorry for my bad english, hope I make myself understandable :-) ) |
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