Quote: Interesting thread topic................the 360 has a longer stroke and shorter rod.............383 has longer rod, shorter stroke. Lets overlook the 23 more cubes to the 383 for moment...........
typically that 383 will get you better efficiency/mpg at a slightly higher rpm. The 360 will give you more torque off idle/low rpm with the longer stroke and more agressive rod/stroke ratio...............
where is this going???? With the 2.94 gearing and LOTS of mileage..........I'd be looking to do the 360 UNLESS it's all interstate travel.
I, personally, wouldn't want to feed a thirsty V8 on a high mileage daily basis. If I had to, I'd build it for max mpg and big torque down low where it's going to spend all of its time.
I put LOTS of hours into porting a set of 516's for a .060 over 383 in my 69 RR. Did the MP porting templates. Went 1.74 exhaust valve too. Just gasket matching, opening up the bowls, working the valve guide boss can all run into lots of hours. And I think with a mild cam it would raise the efficiency of the motor such that it isn't a detriment to mpg. My RR got 14 mpg hwy to Indy from MI with a 750 AFB, single-plane, 484MP cam and 3.91 gears. Not a gasmizer deal at all but it did like to run at 3000-3400. I gained 2-3 mph thru the traps too!
A 383 can be built to be efficient as can a 360. the question is simple how hard are you willing to spin the motor at cruising speed. Since it take extra fuel to keep a short stroke motor accelerating (under load) vs a longer stroke motor, it would be much more feasible to build a motor with more low end torque in it. Since you do have 95% percent of the parts for the 383, build it. The Whiplash cam WILL raise the cylinder pressure (increase static-EFFECTIVE compression) by allowing cam timing events to happen sooner in the combustion process. The two things you must do to "maximize" your power/efficiency/mileage goals is to degree the cam CAREFULLY!! Cam timing is critical and I'd make sure the damper is indexed properly for ignition timing/tuning purposes. Old dampers could have their ignition mark OFF by several degrees! All the above mods/checks can net you a smoother, more efficient motor. The K.I.S.S. (Keep It Simple Stupid) principle always works!
Between the Whiplash cam and the shaved heads (later on) i should be doing okay dynamic compression-wise. Everything but quench... which would really be nice for the end-goal here.
A 383 can be built to be efficient as can a 360. the question is simple how hard are you willing to spin the motor at cruising speed. Since it take extra fuel to keep a short stroke motor accelerating (under load) vs a longer stroke motor, it would be much more feasible to build a motor with more low end torque in it. Since you do have 95% percent of the parts for the 383, build it. The Whiplash cam WILL raise the cylinder pressure (increase static-EFFECTIVE compression) by allowing cam timing events to happen sooner in the combustion process. The two
