Yeah Warren, we run these things WAY too hard IMO.
Most of these engines don't even last one full season... 40 nights at best!
Heat, and dirt, and torque thrashing... on and off throttle constantly....
Well, I just got my first Lttle M engine this past season. It was originally built by Dennis Millert out of Kansas City, (who allegedly builds Clint Boyers' dirt late model engines). I bought it used with only 24 nights on it, but when I switched from Alky to VP 110 something went wrong and burnt six pistons. It was a 388 CI using a 3.625 stroke, 6" rods, and 4.125 bore... all brand new Dart 400 mains Little M with Dart Platinum heads, and all Comp roller cam top end assembly.
Wow that engine was the strongest I have ever driven, and several other experienced race buddies drove it and cofirmed the same.
But, my current engine builder, Mike Elmore, convinced me to get all the cubes I can so he talked me into a 404 CI rotating aseembly (+.020 bore to clean up the burnt cylinders), but flat tapped cam to be IMCA legal.
He just got it done and broke in, and it sounds even stronger than before. I have right about $13K in this engine now, and am almost scared to even put it in the car for next season. With the financial hurt I am in now, if it blows again I am out for good...
Personally, I don't think I would run ANY oil restrictors in a Dart block... that is why I got my Dart engine so I wouldn't have any more oil cavitating or overpumping problems with its primary selct oiling system.
Since this is my first Dart engine though, I will just say that is just my opinion, and may find out differently as time goes on.
Let us know how yours turns out and what is does... thanks, Jim