340 Horsepower ?

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two_70darts

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Hi Just Have A ? About Hp My Car My Have Have A 340 Bored 60 Over X Heads Port Mached To A Rpm Air Gap Man. 750 Cfm Carb Tti 1 5/8 Step Headers To 3 Inch Exhst. 10/1 Comp Pistons Heads Decked Min.for Clean Upcam Is Small 420lift 108 Rv Cam Comp. May Be Higher Due To Carbon Build Up It Will Ping If Advanced Past 6or So Deg.cam Is A 300 Horse Tow Type ? Any Info Would Be Apr. Just Curious What Some Folks My Think.thankz Alot Eastbay All The Way
 
I would change the cam, Its smaller then the stock 340 cam is. A bigger cam may help keep it from detonating.
 
I Do Have A 508 Cam Some Where In That Garage New Lifters And A Set Of Roller Rockers But Still Wondering About A Hp Fig. Guess Ball Park ? Also With Decked Heads Should I Use Lifters Sup With Rockers Heads Where Min Cleaned ALSO CHECKED COMP ON MOTOR 5 WHERE IN 200 RANGE 3 IN 175-190 RANGE BLOCK IS A BIT OLD ON REBUILD 150,000 OR SO
 
I would say your probably around 300hp. The 509 would be to much cam. what gears are in it ? Is it an auto or 4 speed ? Stock torque converter ?
 
323 Gear At Shift Kit Mild Stock Conv Has Over 250,000 On Conv. Drove Car For Days BUILDER DID SUG THAT I CHANGE CONV. AND REAR TO 3.70 + 509 CAM A BIT BIG DUE TO ? SORRY FOR SIMPLE ? BUT THATS WHERE IM AT THANKZ ALOT FOR ANY HELP, ALSO ROTATING ASSEMBLY WAS INTER. BALN.
 
The 509 cam has a lot of duration 9248* @.050") and a tight lobe separation. It needs high compression, 4.10 gears and a 3000rpm converter to run good. Other wise it will be a real slug.

I would use something closer to the stock 340 cam.
 
10:1 would be ok, 323s and a stock converter wont be. It also wont make much vacuum so power brakes and AC wont well. It would also work better with some ported heads.
 
Thanks For All Info Car Is A 70 Dodge Dart 340 Black On Black With Ac And Non Pwr. Brakes The Help Is Great Thought Of A Gear Vender Unit And 410 Possible
 
We know the stock 340's were under rated @ 275. A few years ago, Dick Landy rebuilt a 340 to stock specs. only .030 overbore. With the AFB manifold and carb, it made 315 on his dyno. NHRA factored the 340 @ 310 when it first came out. The six pac's were factored @ 330. The '71's were also factored @ 330. I too believe that your cam is hurting the heads from breathing up top. Something in the 218-228 @.050 with at least .480 lift range would kick this combo to 350 horse range or more. It can easily make more than 350. 400 horses is to easy with these amazing engines. THE best small block ever. Good luck.
Terry.
 
headsbikesmopars said:
We know the stock 340's were under rated @ 275. A few years ago, Dick Landy rebuilt a 340 to stock specs. only .030 overbore. With the AFB manifold and carb, it made 315 on his dyno. NHRA factored the 340 @ 310 when it first came out. The six pac's were factored @ 330. The '71's were also factored @ 330. I too believe that your cam is hurting the heads from breathing up top. Something in the 218-228 @.050 with at least .480 lift range would kick this combo to 350 horse range or more. It can easily make more than 350. 400 horses is to easy with these amazing engines. THE best small block ever. Good luck.
Terry.
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i apreciate the info im going to put in a new cam can any one comment on my compr. diffr in cylndrs 5 of them have 200 psi 3 are at 165 to 185 just used spark plug comp tester probraly my first mistake just an old short block hone or re sleeve or bag and tag keep on side lines for stock purposes?:binky:
 
200psi is to much for pump gas. A bigger cam will help that. I would look in to the low holes though.
 
Yuo either have a leaking head gasket or a ring sealing problem. Are the cylinders on the same bank or are they adjacent to each other? If they are adjacent then you have a leaking head gasket. Does the motor have any blowby? If so then you will have a ring sealing problem.
 
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