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#61
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Hi All
To answer the question 8.11 @ 85.6 mph translates into ~ 12.80 @ 104 mph this varies with which conversion you use 1.57 or 1.5832. The engine is very basic not a race engine. The magnum heads are responsible for a lot of torque on Westech's chassis dyno put at the crank 370 Hp and 430 #ft of torque at the rear wheels 300 Hp. It idles at 850 in gear and is very driver friendly. The torque never was below 350 #ft from 3000 to 6000 over 400 from 3200 to 4500 rpms. I'll be at Mopars at the Strip to see what the 1/4 mile numbers are.
I feel that the magnums are the best iron head for any mild small block if your looking for torque. The chamber size raises compression, the quench is better. The balance between intake and exhaust is better than any LA head even ported ones. The intake volume is less than LA heads, 153cc's for magnum @ .600" lift 190 cfm, 166cc's for LA @.600" lift 170 cfm so which head would you want ? The bigger that flows less or the smaller that flow more ? Does velocity mean anything to you ? The numbers are from the MP catalog 2001. hope this helps denny |
#62
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Back from Vegas
Hi all
Just got back from Vegas and best pass 12.83 @ 105.6 corrected for 2900 ft altitude... Car weight is 3315 with 3/4 tank of gas, and with my fat butt add 330lbs makes 3645 lbs . This is ran with 235/6015 tires 3.55 sure grip, 2400 stall(166K) A727 , M1 dual plane, 650DP Demon, Magnum truck heads, cam is 230 @ .050, .511 lift due to 1.6 rockers. This is a very simple combination easy to build and easy to maintain. Denny P.S. Magnum heads don't work "?", splain that one "lucy".... |
#63
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Im glad to here those numbers. Im building a Mgnum headed motor also. I have a XE274H and will use a new AirGap. I havent decided weather to bolt this stuff to my currant 340 or to build a 360 short block yet.
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#64
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answer to me is simple
hi
Build a 360 for these reasons cubic inches, stroke lengh 3.58 vs 3.31. The torque is greater for nearly the same displacment, the 340 will rev higher but not build the torque to move the mass at low speed... |
#65
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I've always heard this bull about how a 340 will rev higher than a 360 for years. What bull. I've turned 318's and 360's in the 6800 range all night long. And I know others that have too. All you need is the propper combo and every engine will turn just as much rpm as the next one will.
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#66
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when it comes down to it, if you build all of them the same, with close to stock internals,the 340 is the lowest rpm of them all
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#67
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No, if you built them the same with the only real difference being of course, piston/bore/stroke, the 318/340 revs quicker and higher due to a shorter stroke. The long stroke will not rev higher. Piston speed reachs a higher speed/velocity faster and sooner.
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#68
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LA360Dart;
Were the heads ported and what valve sizes were used? Thanks. Good post! |
#69
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DWC you can't read or comprehend english very well
Hi dwc;
Once again dwc you have failed to understand what I was saying. The 340 must be rev'd higher to make torque where as the 360 will make it's torque lower in the power band. I never said that you could not rev a 360 but that, and listen carefully that a 360 will build more torque at a lower rpm than a similarly built 340. Maybe if you read the post rather than flying off the handle you might see that nothing was said about rpm limit of a smallblock by me, the 14,161 posts might have some value if you read english better. rumblefish360; The valve sizes are 2.02 and 1.625, gasket match bowl work and chamber unshrouding for the 2.02 intake valve... |
#70
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DWC you can't read or comprehend english very well
Hi dwc;
Once again dwc you have failed to understand what I was saying. The 340 must be rev'd higher to make torque where as the 360 will make it's torque lower in the power band. I never said that you could not rev a 360 but that, and listen carefully that a 360 will build more torque at a lower rpm than a similarly built 340. Maybe if you read the post rather than flying off the handle you might see that nothing was said about rpm limit of a smallblock by me, the 14,161 posts might have some value if you read english better. rumblefish360; The valve sizes are 2.02 and 1.625, gasket match bowl work and chamber unshrouding for the 2.02 intake valve... |
#71
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I read it, and my post count is just fine and really has not a thing to do with anything other than I help a lot of people.
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#72
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Quote:
your car is very respectable that is pretty fast, expecially for a dual plane, mild cammed engine. good job! them magnum heads must work good! now, because ive been acused of being a smartass, i can adress your smart asss comment right?????????????? BIG WHOOP! there are flathead fords that can run mid 12's! :jackbox: :blast: :flip: |
#73
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Well then your comprehension is suspect
I was responding to fastback340 and you chime in about how " a 340 will rev higher than a 360, what bull " My statement was about the chioce of a 340 vs 360. Not the RPM limits of either just where the torque is in the power curve.
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#74
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It's the same thing with all engines. If the air flow dictated by the cam, heads etc remain the same, the more you have dispalcement, the lower the rpm where it's most effective. Longer stroke also tends to prefer lower rpm,e piston speed is propably one factor here. With more stroke your piston speed is higher. Everything being equal as far as the CR, heads, intake, cam etc go, a 360 should be more "friendly" engine than a 340, and produce a little more power too in a street/strip style engine. You don't need as much gears or converter with one.
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#75
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dodgetkboy78, it just dawned on me that your statment has a point. The 340 pistons are the heaviest of all.
LA360Dart, Thank you. DartGT66 Good post, like this comment. "piston speed is propably one factor here" this is the most important part of it. A Longer stroke engine develops higher piston speed or should I say max speed faster because of it's long stoke. If all three engines were built the same......the answer becomes clearer. |
#76
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Quote:
well, good job, thats real fast for a mild street car! im impressed (really) cause there is a lot of em with your combo that do 14's. although, i never said they didnt work, they just dont flow as good modified, too much interfernce in the intake port (bottleneck) and not enough roon in the roof to hog. no biggie, i also dont like the non rockershaft system (although it seems to be tough) now, for the smart ass part? (he he) Big whoop, flat head ferds have gone that fast :blast: :jackbox: |
#77
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Ported magnum heads will flow around 250cfm @.500" if done right.Thats pretty good flow. Although if I needed something better then the stock Mags I would go with the RPM Magnums. they will flow 260 out of the box.
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#78
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What about going with the throttle body inj. 1987 up non magnum swirl head? They have longer exhaust ports, a higher compression ratio and they're cheap.
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#79
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By the way, I have a friend with an 8000RPM 340 stroker. He uses the MP 4 main block and an eagle crank and H rods with forged pistons @ .040 over. He has fully ported and polished indy heads and single plane intake. It hits 8G off of idle instantly.
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