Not exactly the same thing, but my 76 had a Holley on a 350. It did great on the highway, but did not tolerate being driven slowly around in the woods. It would flood and barf gas all over the top of the engine!
I got a Qjet from a junkyard and had a neighbor rebuild it for me. Worked fine after that.
Nice truck, BTW
So does it also have a small engine pump? The PTO pumps don't work very well for "pump and roll" operations. But maybe you're just doing stationary structure protection. I don't know your experience but let me know if you have any wildland firefighting questions.