I can say I am rather experienced. Especially in mud racing. We mud raced for a total of around 6 years. And during those 6 years we used the same 1979 high sierra with 38 inch tall tires and 3.08 gears. it was the full truck not cut up or modified. During those years we learned alot about engines and how they respond in the mud. We didn`t race in the little ankle deep skim mud, the track we raced at used deep thick clay mud. We started out with a 350, and in the first year won most of the races held, even against big blocks. The next year we did well again with a 383, but not as well as we did with the 350. The year after we got our butts handed to us, we only placed once, but, we made a mistake and that mistake was a 372, 400 block, 350 crank combo. even with a 3000 stall, we put too much cam in it. The cam was 234/244 duration at .050 and it had no low end power whats so ever. It would rev to 7200 rpm but no matter, the heads we used ran out of breath at 5000 and it didn`t make any more power after that point which is the same thing Curtis has already mentioned. If the head can`t flow it, it can`t make anymore power. Years later we returned to mud racing when another track opened. this time we used the same combo as the 372, same cam, same heads only we used a 400. the first 2 years we kicked butt and took names. Then my brother in law, the owner of the truck, got ambitious and wanted to step up, so he installed a massive solid lifter cam, duration of around .255, and a set of 200cc runner dart II heads. I was against this idea, the heads I agreed with, but the cam I warned him was way too big. He chose to use it anyway. Now this is a 400, 50 cubic inches bigger than your combo and the cam size is close to the same, but the dart II heads were made for upper RPM power. The thing sucked, it was lazy and didn`t make any power until the revs reached 4000 rpm, from there on it screamed. Once it hit the deep mud and engine lugged below the power band the game was over.
Sorry, but I don`t call your package well rounded, I can tell you from experience it`s not going to work as well as you think it will. When your trail mud riding you need control, and you can only have that with low rpm torque, you don`t have that control when you have to rev it to the moon to make it move.
Lastly, It wouldn`t matter to me if you have 40 years as a engineer, there is no substitute for experience. Curtis is well respected on this site and is very very knowledgeable. And myself I just listed my experience in this. But, if your age is stated correctly then I will say respectfully you have a lot to learn, and your only going to learn it with experience. And that type of experience is build it then get out there with it and see what happens.
Were only trying to tell you before you do it you have a mismatch.
Good luck. Let us know how it works out.