yep.. I see my mistake now that I read back. Had it right the first time.. then I got it wrong, then I got it right again. Hey, it was late after a long day and at least I understood what the hell I was trying to say. lol I know you didn't want a link.. but maybe others can learn from it. The conversion can be done several way but we water it down to the typical formula. Still all works out the same though even though I pooched the shorthand terminology. http://www.hotrod.com/how-to/engine/hrdp-0401-torque-horsepower-guide/ Decent article with big name quotes but shows that even the pro's have various viewpoints. Yet they all manage to be at the top of their respective games because they are still designing successful engine programs. More than one way to skin the same cat. As usual. This thread lacks sufficient info to even help us help anyone with an engine build recommendation. Screamer?.. or a brute?
Bottom line to the OP is, don't let anyone talk you out of building a 331. You will not be dis-satisfied with the end result. I built mine with "middle of the road" heads (Canfield equivalent of the AFR165's) The choice of the Z303 cam was a spur of the moment thing, picked it up for $125 (New in box) The 3x2 induction was a conscious choice having heard a Pontiac setup in the 70's at WOT in a car with quiet exhaust (the sound is quite unlike anything you've ever heard) The end result was nothing short of pleasing to me. The powerband is perfect for a daily driver, although it'll put the car sideways in 1st and 2nd and it's even squatted sideways a bit hitting 3rd and has a healthy lope at idle. It'll even get 15+mpg on the freeway at 70 mph. If you want more topend HP, then go bigger on the heads or cam or use a single plane intake. Just remember those numbers at the topend will rarely ever be used in a street car, when you do you'll stay in trouble with the boys in blue. (the cops) The 331 is basically the old Chevy 327 in a Ford package. Ask any of the old timers what they thought of the 327, you won't hear a word said against one (other than it's a Chevy)
Rob is right about the expense,& the man w/ the most money if he can drive will usually win.I have most of the parts now for my 408 bottom end & here is what I am up against.My forged crank will weigh 54lbs,rod & piston combo 925 grams excluding bearings & rings.The racing Chevy small blks & LS1 cranks only weigh 43 to 45 lbs,not sure about their rod & pistons.So I am 8lbs heavier on the crank right away,what this means is they turn up quicker & it takes less power to move their internal parts.I am using the 3in main crank,if I had the money I`d buy the World or Dart blk w/ the cleveland mains & would be more competitive,I will just have to be happy w/ what I have.
Google " 306 vs 347 Mustang 360" for a cool head-to-head test on a dyno with just the short block being different and a bit of tuning being allowed. MD
