edelbrock performer cam is a good one.
I like the competition cams 268 grind too
194 valve heads running 9:1 compression and a cc 268 cam 650 carb and perf. dual plane intake and 1.75" headers will net you around 330 hp
I built a couple of those. I had one in a 75 c20 full time 4x4 that got 10 mpg in town and up to 15 on the highway... full time 4x4 4:11 gears 4" lift and 36x12.50 goodyear wrangler II's
My favorite intake on that combo or grunt was the holly 650 double pumper. and the weiand 8000 dual plane intake.
I put on a 650 edelbrock carb and performer intake and picked up some reliability (no power valve to go out) but lost a little power on the passing gear
106 and 108 degree lobe centers are good for racing cams
112-114 degree lobe centers are good for torque and midrange
you can take the lift and duration of a mid level lumpy cam (that's probably running tight lobe centers) and smooth it out by spec-ing that lift and duration on a wider lobe center angle like 112-114 degrees
While increasing lift and duration does increase your overlap...
Tightening the lobe center increases overlap too.
that's good for upper rpm breathing but it hurts lower rpm vacuum and torque.
overlap is the period of time measured in degrees of crank rotation that the exhaust valve is still open while the intake valve is open too.
Yes it is true...the intake valve opens before the exhaust valve closes...
it's the overlap that makes a cam rumpy. Exhaust reversion at lower rpm's back into the cylinder is the culprit. at higher rpm the inertia from the exhaust speeding out of the cylinder pulls in air fuel better then just atmospheric pressure from the carb.
you can increase low end power and keep a stock idle by running 2:02 valves instead of 1.94's...
by running a 3 angle valve job,
and by going a little bigger on lift and duration without increasing your overlap.
there is alot to be gained in tuning your engine (cam, valves, carb,intake,headers, etc) without making the thing radical.
going too big on the parts can hurt performance also
the lumpy idle isn't what makes power, it's the result of a tradeoff.
the engine is running rough because of low vacuum signals to the carb and uneven cylinder filling. It is actually making less power than it is capable of...at the rpm that it sounds rough.
but it sure sounds good
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Your maxed out engine isn't going to make any more bottom power beyond a certain point. after that you have to spin it faster to find more power.
the catch 22 is that tuning for upper rpm power takes away from an optimum lower end tuning.
I put together a 460 for my pickup that puts out 375 horsepower at 4500 rpm, 450 ft/lbs of torque at 4000 rpm and gets about 8 mpg city and 10-11 highway in a full time 4x4...not much less than a 350.
It idles smooth as silk and sings like a hell when you open it up.
I can be rolling along at 60 mph with a car on a trailer and pull out in the left lane and pick up 10-15 mph in a few seconds.
