Re: Power Options for 327
Only difference between a 302, 327 or a 350 (or the 383 that Chevy never built) is the stroke. The longer the stroke the more torque the motor will make overall, and the lower in the RPM band that torque will build. It is torque not horsepower that accelerates a car. That torque is what your butt dyno tells you and defines a fun ride. A 302 can make 500 horsepower in race trim but it has to stay above 8,000 RPM to do it. 8,000 RPM launches will get you arrested in most states not to mention being hard on parts.
GM developed the 350 and the 400 small block in response to heavier cars requiring more torque to get them moving (the 1970-'76 Impala was the heaviest car Chevy ever made). The 350 is a 327 that is stroked to what the engineers at the time though was the maximum. The 400 proved them wrong when it came out with the 3.75 inch stroke used to build a 383 in 1970. The difference between the 400 and the 383 is the bore.
In my opinion you build an engine with the biggest displacement you economically can. This is especially true with a short stroke 4.00 inch bore block because to make the same horsepower with a 327 as you would make with a 383 you have to rev it to a higher RPM. Often above the physical limits of a hydraulic cam.
A hydraulic cam limits RPM for two reasons. First at higher RPM the lifter pumps up keeping the valves off the seat. You can not bill power with the valves open. Second at higher RPM you get into valve float because a hydraulic lifter will collapse under the stiffer spring rate required of a valve spring that can close the valve at RPMs above 6,000.
So you must be willing to settle for less power and less torque with the 327 because of today's gas that will not support the higher compression that the "classic" 327 had in the days of muscle cars. That 360 horse 327 had 11.0:1 compression with cast iron heads. It did however have a very aggressive for it's day hydraulic cam. The top dog 327 had 12.5:1 compression and solid lifters to rev even higher.
Horsepower is a function of torque applied over time (revolutions per minute). In racing, which is often a timed event, you must be willing to rev to the limit of the engines endurance to win.