I have another 3.90 stroke 440 block pump gas motor I will test next month, if the money allows that On this one the RPM intake probally limits the peak HP RPM, I looked at the sheets the dyno operator sent me, there hard to read by E mail or Photo Bucket It looks like the motor made 506 HP at around 5700 RPM and 570 Ft. lbs at a RPM I can't read, I'm guessing between 4000 to 4500 RPM As far as the jetting on the 4781-2( the second carb. tested) I had 78 in the front with a 6.5 power valve and 86 in the rear with no power valve and no other mods. I'm aware of or did other than having the choke blade removed. On the first Carb, 4781-7 I did open up the H.S. bleeds to right at .028 or .031, CRS It ended up with 76 jets in the front and 74 in the back with power valves in both metering blocks like stock I think thats the jetting and H.S. bleed sizes, CRS again It really suprised me when the earlier carb did better with stock jetting than the later carb. did I guess that is why we test I will switch manifolds on the next motor, take off the RPM and put on a either a Mopar M1 single plane or my old favorite, the Weiand Team G single plane I'm hoping to get some printed copies of those results soon so I can read all the data instead of parts of it All in all it was a good day, nothing broke and it made 40 more HP than it started out with BTW, making the AFR leaner did reduce the torque but it improved the HP, at the track by using a wide ban gets the same results Leaner is faster than richer. We don't race dyno ,do we My old M.W.stocker out ran the other cars in the same class that had hot spark plugs and a rich mixtture Test, test and test some more, the spark plug and time slip is your freind