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cam to make 400hp

mopar3404bbl

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I will be hand porting my heads myself. been watching enough videos and reading enough books to do it myself. got a pair of spare heads to practice on. any how. with heads and intake port matched, 750 cfm 4bbl carb, hooker headers, 3.73 gearing 4 speed. looking for a camshaft to compliment it to make atleast 400hp. right now I got a purple cam. believe the specs are 268/268 474/474 why is the lift so low? was looking at a lunati 276/289 513/533 110
 

moparleo

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First, welcome to the site, when you get a chance head over to the Welcome wagon and introduce yourself. Second Engine size, head type, valve sizes, open or closed chamber, stock or roller rockers, stroker or stock, header size diameter, length ? This information would make it a lot easier to recommend anything you might need
 

mopar3404bbl

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First, welcome to the site, when you get a chance head over to the Welcome wagon and introduce yourself. Second Engine size, head type, valve sizes, open or closed chamber, stock or roller rockers, stroker or stock, header size diameter, length ? This information would make it a lot easier to recommend anything you might need

340 everything is stock other than cam
 

burntorange70

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Bunch of 340 making close to that. Carb, intake, headers, cam, should get you close. Head work should get you closer.
 

mmissile

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Getting to 400hp isn't that hard, but making it work to it's potential requires every bit of the drivetrain be put into the cam grind/design.
 

Chryco Psycho

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The Mopar cams are 40 years old , newer cam profiles have improved , the Lunati VooDoo are a better design but over .500 lift you will need better valve springs , trimmed valve guides & you need to check piston to valve clearance
 

moper

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You should probably look into the heads deeper than the porting. A performance shop can do wonders just by doing a decent valve job on it using 5-angle cutters. Then you're not spending so much time making iron dust. You'll also want to make sure the guides are perfect. You'll also want to keep things as small as you can port-wise. Smaller is better than huge.
As far as the cam - anything modern (read as NOT the MP stuff) with a duration around 230°-235° at .050 of lift will get you close. That Lunati will do it but as Chryco said it needs the spring seats cut, and the guides cut, and adjustable rockers and matching pushrods to get you there.
 

hot metal

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Well if its a '72 340, 8.5:1CR which is not stated you got a job on your hands to get 400hp.....if earlier 68>'71 your at 10:1ish?....even then I can't see 400hp without working the heads to flow at least 240>250cfm with a good v/job etc., get the heads flowed once ported then you can pick a cam that suits the figures keeping duration sensible as suggested above for good CP.

My old 1971 340 motor with stock just cleaned up T/A 2.02 heads, .590" solid cam, Holley SD intake, 2" spacer, 850DP and race 1.3/4" hdrs made a real world 365hp at the track.....ran 108mph at 3550lbs, it could've been better but we didn't have machine shops everywhere to blueprint everything then. 400hp is not as easy many say with stock parts, even with "modern" cams! The heads are the key, the rest needs to match giving consideration to use, get into 270+cfm heads and then yes your there and then some at 340ci...my2c

And regarding making 400hp with a stock 340, this is what it took for 1 guy, from a post from another site>

1969 Barracuda FB 340 +.060 ...12.5 to 1 TRW, stock rods, X heads with 2.02 installed. MP .590 cam, Holley strip dominator with 750 DP, MP electronic distributor with MSD 6AL, Hooker 1 3/4 Headers,
904 trans with Tranzact Brake, Turbo Action 8 inch Converter flashed to 4800 rpm, 5.13 gears with M/T 14 x 32 slicks. Car weight with Driver 2700 lbs.
10.90 @ 121 at Bakersfield in 1990 = 412hp
 
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