340 buildups

I just built a 360 with magnum heads. It's has zero deck KB107 flat top pistons, and 0.039 head gasket which results in 10.6:1 compression. I am running a Comp Cam XE268 cam, with a Professional Products CrossWind dual plane manifold (copy of an Edelbrock RPM Air Gap). I have 1 5/8 headers with a 2.5" dual system with a x-pipe and Flowmaster 50 series mufflers. I am currently running a holley 600cfm vacuum secondary carb. The engine is in a 68 Barracuda with a A833OD 4spd and 3.55 geared sure-grip rear end. I now have a little over 1500 miles on the car since installing this engine. Below are my impressions;

* The engine is very strong. It has instant throttle response off idle. Nailing the throttle at any rpm above 1000 to 3000 in first gear and the back tires go up in smoke. A hard shift to second and the back end steps out with another cloud of smoke. The engine does not lack for low rpm punch :)

* The engine continues to pull hard right up to 5000 rpm but starts to roll over at 5500. I believe a bigger carb will help but both the cam and intake are geared to make power from 1500-6000 rpm. I have been looking to borrow something in the 700 to 750 range to try but I don't want to loose the crisp response on the bottom end where I drive the car.

* The Comp XE268 cam is a hydraulic but it is noisier than is normal from a hydraulic cam. The brain trust here as well as Comp feel that it's a nature of the very aggressive lobe profiles. Most people ask if it's a solid cam.

* I have no detonation problems with the 10.6:1 compression as a matter of fact it runs well on 89 octane. Gas mileage was not a consideration when I built the end but with $3 gas I have been checking and it's getting about 15 mpg around town. The 600 cfm carb is jetted a littel rich so I hope to find the time this weekend to do some jetting and maybe squeak a littel more out of it.

A 340 will not have the low end grunt the 360 has but you can expect pretty much the same characteristics from a similar 340 build.