Chris, read this before you make the change http://www.uvm.edu/~pmrc/Combustion.pdf
I did it back several years ago. I used to get stack temps of 1400-1600 F and had a ball of fire out the stack as unburned hot gasses got to more oxygen. I also had sparks out the stack.
Then I built a modified version of how the instructions say to do it. I can't say how much HP air mine because my blower is from 1904 and is belt driven by a 1 HP motor, but it works wonders. I used 2" square tubing, set 6" below the pans with nozzles pointed down at the prescribed angle of 10 degrees downward, spaced every 6" from one side of the fueling door, all of the way around the firebox to the other side of the fueling door. My HO blower is outside, under my head tank platform, it blows in thru a 4" PVC pipe with 3 long sweep elbows, then it splits into 3 pipes that are 3" diameter. One feeds a heavy galvanized pipe, 4", that runs in under the arch. It has 3 rows of holes, one top center and one on each side facing almost to the outer edge of the grates. The other 3X feeds a 2" square tube that drops down from the arch ramp at the back of the firebox. From there it feeds the 2" square tube. Each of the 3" pipes has a 3" brass ball valve to regulate the air flow. I'd need to recheck but I think the one feeding the AOF is open about 2/3 and the one feeding the AUF is open 25-30%. Each of the nozzles is 3/8" black iron pipe. I removed the firebrick to install the manifold, then ran a layer of full firebrick above the manifold and used plastic refractory to protect the manifold tubing and above the brick to the top rail. My ball valves were adjusted several time during the first season, until I decided where they are now is best, since then they have never been moved again. Those valves would not likely be 3" brass ball valves but I got them at $.10 a pound at scrap prices. The blower was $.02 a pound with the motor too. That motor just quit this season and I had to buy a new one. The old one had a patent date on it of 1895.
Before I did this my boil rate was between 55-65 GPH, and I added wood every 7 minutes. Now I get a boil rate of 75-85 GPH and add slightly less wood each time and at 9 minute intervals. I can also add at 8 minute intervals and get 85-90 GPH but things move too fast for me that way, so unless I have experienced help in the sugarhouse I do the 9 minute fueling. My stack temps are now at 750-1100 F, I get no sparks nor ball of fire at the top of the stack because the gasses are burned while still under the pans where they do more work.
As I say, mine is modified, the write up says a 3" pipe to carry the HP air to the nozzles, mine is 2" square and the blower is unknown. I could get it tested for pressure but it works so well I don't worry about it, besides I get syrup fast enough. My plaqns were to cut the nozzles back to even with the brick, but then I decided to leave the excess and just let it burn off, that didn't happen and the nozzles still look new, likely because cold air is keeping them cool. The nozzles stick out 1" to 2.5", but that has not proven to be a problem.
I start my fire by laying the wood up alternating it for best air flow then I use a weed burner torch. As soon as it is going, I turn the blower on and it stays on even during fueling until the coals are burned up at shutdown, I don't even turn it off to fuel. Initially I did shut it off, but then my grandson forgot to shut it off one time and I noticed it made no difference, then it was no longer shut off to fuel.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.