Good morning gentlemen,

I currently have a 440 sitting on the dyno with somewhat disappointing results. I pieced together a combo that I had hoped to make north of 550hp but am falling about 30HP short of that. The first thing that has me somewhat confused is that the motor is only pulling 680 cfm through the carb. I would have expected at least an additional 100 cfm. The torque curve is good and amazlingly flat from 3000 rpm up to 5000-ish making at or above 500lbft through much of the curve. The motor peak hp at 5600 rpm ended up at 519hp and fell fairly quickly after that. By 6000 rpm the motor was done making power. The builder says I need more cam (duration), I think he is wrong and something else is choking the motor. I have posted the 1st dyno run numbers which was a short pull but is consistant with the following pulls up to 6k. 32 degrees of timing on pump 91 octane gas. What do you guys think?

Here are the motor Specs:

Stock stroke 440. Cast crank & LY rods
ICON 968 .030 pistions. Zero Deck height
Compression is just a smidge over 11.1:1 with .039 gasket
Toth Ported ProMaxx heads (300+on flow bench) cfm on intake Finished Chamber is 76cc
PAC Springs and Comp retainers/locks
Hughes engines Solid Cam STL5054BS3-8 BB SLD FLAT TAPPET CAM 250/254 -108ºLSA 3 BOLT .392"/.400" LOBE LIFT: Gross Lift I .627/E .640 with 1.6 Rocker
Hughes Roller Rocker 1.6 ratio
Trick Flow single pane intake, port matched.
MSD Dist/Ignition Set at 32 degrees at full advance.
Melling HV oil pump and Milodon pan.