548 hp at 5500, 580 torque....
Wow! Killer torque. Was this with the 780 carb? Awesome build!
Yes sir, a Quick Fuel HR-780.
Here's the dyno sheet. A little bit of an A/F ratio imbalance from side to side. Could have been the way I shaped the divider, not sure, but a Super Sucker didn't straighten it out and neither did a large air cleaner. Regardless, it's showing lean because we were tuning for 4500' altitude on the last several pulls since this engine is going to Wyoming. Makes it a little trickier to manage time efficiently, because we wanted to make sure that it would be close enough on A/F so that he wouldn't have to do a lot of tuning once he got it in the car. We can even "drive" the dyno to simulate the A/F ratio at cruising rpm, and spent time tuning for that scenario as well.
The torque surprised me as well. Dynos have a range of repeatability but all torque numbers after the majority of tuning was completed were in the 570-580 range.
One thing to note: we watch the oil temperatures throughout a pull, as it can be an indicator of issues. We typically see 2-3° bumps in oil temp throughout a full pull. There's a trend with the Canton and Milodon pans, in that they are so deep that the oil temperature will start going down through the pull. The dyno cell has airflow in it and those deep pans act as a radiator. Pretty neat.
All-in-all, I was very pleased with the engine and I'm a big fan of these cylinder heads. Making almost 550 hp with a 5500 rpm peak, holding to 6000 with a relatively small camshaft (231° @ .050" intake lobe) says a lot for cylinder head performance.
