Hi, I have a bbc engine 454 bored at .30 with flat pistons, compression ratio is 9.80 to 1 with close chamber heads, (rectangular, casting #3919840) 107cc with 2.25 intake/1.88 exhaust inch valves, 1968 out of a 427 engine in my 1970 SS Chevelle. Just wondering which comp cam kit would be most beneficial to my engine and as far as getting the most Horsepower and Torque out of it. Each Kit comes with matching valve springs, lifters, timing chain, steel retainers and locks, and hydraulic cam.

CCA-SK11-242-3* Grind (xe268h) Specifications:
* Advertised duration: 268 intake/280 exhaust
* Duration at .050 in. cam lift: 224 intake/230 exhaust
* Gross valve lift: .515 in. intake/.520 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 1,600 to 5,800
*Slightly rough idle quality

CCA-SK11-246-3* Grind (XE274H)Specifications:
* Advertised duration: 274 intake/286 exhaust
* Duration at .050 in. cam lift: 230 intake/236 exhaust
* Gross valve lift: .552 in. intake/.555 in. exhaust
* Lobe separation: 110 degrees
* RPM range: 1,800 to 6,000fficeffice" />>>

I have a 1967 camaro with a new 454 (.03) over with afr rect port cnc 305 cylinder heads, 10:1 comp, and a magnum 290 roller cam and i made 573 hp @5800 and 564 ft lb. I wish i would have went a step bigger the 232 int/exh duration wasnt enough for this motor. I would go with the xe-274 cam for your application.  However look into getting a roller cam for some more horsepower federal mogul makes retro fit roller rockers for bbc for $350.  I would definitely go with a cam over 230 of duration on both the intake and exhaust use either a rpm air gap or a victor jr. intake.

I hope this helps just make sure your rect port heads flow enough air for high rpm and you will make some strong numbers.

                                          Phil

Lets get the debate started. Rectangle heads are a poor choice for the street, especially closed chamber. Large oval ports are the way to go everytime. If you have spent time and money on the rectangle heads then you will have to make the best of them. I believe there is a In. manifold that adapts oval size runners to rect. ports in an attemt to get the In. charge at a higher velocity. As far as cams go, if you have the money, go with a roller. They open-close the valves much faster and keep them at max. lift longer. I wouldnt go to nuts on lots of duration for street use, 225-235@.050. More than that makes your low end suffer. Good low end and mid range is what gets it done on the street.The most important thing to keep in mind is In. closing point. (Big) cams close the valve late and bleed off cylinder pressure, torque will fall off and you will have a narrow powerband that wont be much fun for smoking those tires at the traffic  light. As for the fender shaking idle that you seek, check out the Commp-Cams Thumper series. I believe they come in roller and flat. They just increasd valve overlap to make things run a bit rough at idle. Good Luck.  

Sorry "JW" but I don't think they're going to answer. The thread author posted this more than four years ago.  

Still learning how to use thi site and this dang computer. Did you ever find out what he chose?  

If he didn't post here again, I have no idea!